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PT Cruiser Overheating Issues

Discussion in 'PT Cruiser' started by Quaddriver, Jun 1, 2017.

  1. Quaddriver

    Quaddriver New Member

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    First time caller here...

    I got a Cruiser for my kid who graduates HS today. 2001 Base, 72K, 5spd (for some reason, he like other teens want a stick - they have not learned yet!) and a killer price at auction.

    It went thru my typical new (to me) checkout and seemed fine, but one issue was noted it had no thermostat and on the day I patriated it from the auction, it was a chilly ride. Once I drained the water and used antifreeze and installed an over priced thermostat, it seemed fine.

    Until a highway trip last monday it overheated. I showed the age old 'heater on high' trick and it kept the needle out of the red, so I tore into it and found a TON of sludge in the filler/thermostat neck.

    WTH? Further investigation and testing has found the following, and hence my post. It should be noted that overheating is by far the LARGEST issue reported with the cruiser. Everything I likely will state here may be stated elsewhere and on other forums, but when I went thru a google search, the data is random and haphazard. Since I search first, buy parts later, this may assist someone in the future.

    Part 1: The problem as it were

    1) The cooling system on the PT is way undersized. Period. Radiator size is dictated primarily by HP generated by the motor and can be mitigated *somewhat* by airflow over the core.
    1A) the cruiser has a stylish front end that impedes airflow at low speeds
    1B) typical traffic in the US nowadays guarantees congestion near any population
    1C) the cruiser makes near 150hp which is pretty sporty for a core the size of the tranny cooler on my Suburban

    *all* engines are aircooled. Most of the cooling at speed occurs from airflow (auto engineering 101) and liquid cooling is essentially for the heads due to other issues. A combination of factors (square area, airflow, airflow speed, effective channeling) are all compromised on the Cruiser design.

    2) the PT uses the newer OAT based silicon free coolant which is a mistake - plain and simple. 20 years of actual data has shown us that this coolant is only acceptable when *zero* fresh oxygen is available. Otherwise it forms a sludge that looks like oatmeal and diarrhea. Most vehicles using this have a radiator fill that doubles as the overflow tank and is sealed to the outside, any oxygen in the tank is incidental. On the Cruiser the tank is very remove and is vented to the outside, the cold vs hot volume of the tank varies by about a pint - typical, but each movement flushes and refills the tank with fresh oxygen. This is a different looking, but identically operating system used for example, by the W-motor S/T GM vehicles, which was a disaster using dexcool.

    3) No larger radiator seems to exist. Reserve cooling capacity is extremely small. For example, in the early/mid 80's ford used on the manual trans, ac-delete, I-6 motor F-series a small radiator (larger than the PT by 50%) with a direct drive fan. Capacity was so limited that replacing the direct fan with a clutch fan would result in overheat at low speeds, and this is on a bull-nose vehicle.

    From looking at it, there is no reason the radiator cannot have 2 cores, but none are OTS available. I did not look at the turbo model radiator, I figured where would be other fitment issues on a non-turbo due to the likely use of an intercooler - Mopar tends to get the Turbo 4's right.

    So, next post!
     
  2. Quaddriver

    Quaddriver New Member

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    Part 2: So lets fix a cruiser cooling system.

    1) With a compromised capacity system I know emissions want it, but the 195* thermo is part of the problem. It holds the temp too high in cool down periods leading to longer periods of heat soak say after a highway run (more on that later) or a long stoplight.
    A 180* therm is the ticket - advance auto - no dice in stock. Autozone? Thats a bingo! Duralast part 4208. If you can wait a few days, rock auto is your next bet.
    And drill a couple holes in the face. 2 1/8th inch holes (.125) is the ticket. Yes, it will take a minute longer to heat. Yes, it will go closed loop. No it will not set MIL. Yes you will have winter heat. But the bottom line is, if something sticks, and todays thermos are chinese made crap, you could save the motor. Its an old school trick, but alas I am old school and in 4 decades of screwing parts on motors, aint lost one yet due to thermostat holes.

    2) Flush it, then flush it again. I dont think these modern radiators can be saved and lets be honest, no one tanks em or pressure checks them. They are disposable and the pricing back that up. If you have the thermostat in remove the radiator and put in a low flowing garden hose in the lower and let her run, revving the motor until you have clear flow. It will not overheat and reverse flushing really wont work on this design.
    2a) pull out the bleeder screw and clean the crap from within it.
    2b) remove the overflow hose and either replace (*prefered*) or blow the crap out of it. It will look like the arteries of a 60 year old who lived on meat and cheese
    2c) remove the overflow tank and clean it out, get all the crap out. It will be full, trust me. do not use dish detergent. You aint gonna get it perfect white and any leftover dish detergent will foam the heck outta the motor
    2d) remove the blockage in the filler neck overflow hose connection. It *will* be plugged. Steamy water will get out, nuttin will get back in.

    3) Replace the radiator. Advance: $130 in stock usually. Autozone: $127 in stock usually. Rock Auto: no higher than $90. Amazon.com: $75 for a spectra shipped overnight to your door. (using prime) I have used spectra tanks and rads for decades and have zero negative feedback for the company.

    Yes Virginia, it is that simple. Thermostat, thorough flushing, new radiator, new cap.

    Do you need a headgasket, water pump, connuter valve?
     
  3. Quaddriver

    Quaddriver New Member

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    Part 3: Diagnosing issues

    1) There are two shadetree checks for a bad headgasket: coffee with cream in the crankcase or, bubbles in the coolant. Oil+water mix is an easy one, and even if its just a steam leak, there will be the frappe sludge on the bottom of the oil fill cap. But the bubbles are hard to diagnose on the cruiser.
    If you have a cracked head at the spark plug boss or top of the CC, a rev will produce an immediate and dramatic 'whooosh!' of coolant. Aint hard to spot that one. But, consider this, if the cruiser radiator is the least bit plugged, coupled with its single core diminutive size, it presents a restriction to the water flow and since the thermostat housing is behind the pump, a rev will simply push some water to the path of the least resistance - out. When I just did this radiator, brand new fresh everything, a rev produced - like it would on any motor - a *drop* in water level as the suction pulled it down. This is how we used to burp motors. Most people just used to fill them cold, engine off, cap them, and let the rad cap/pressure tank burp the air. Some did a start and let it push air, heat up, then refill. But the really street smart ones revved, held it, filled it, capped it, then released the throttle. Its only an 8 ounce at most difference, but thats 8 ounces of air volume no longer present. Do air bubbles create a problem in a pressurized liquid cooling system? Dunno, go ask Three Mile Island....

    So in short, the bubble or volume test is not effective on the cruiser.

    2) Is your water pump impellor rusted away? Geez I hope not. I have never seen a metal pump with the vanes rusted off in a *car*. Boat yes, car no. If it produces flow, its ok. Flow is not the primary issues, BTU removal is. If you are not leaking from the pump, leave *that* can of worms for another day.

    3) Sniff testing for leaks aint easy. The overflow tank is well vented to the open air, and if that was not fun enough, if it does spit, it spits onto the exhaust to make extra smell. You will know quickly if the heater core is popped and a rad leak, even just a steam leak are pretty easy to get to (loss of coolant, no white smoke, no oil mix point to a steam leak externally BEFORE a steam leak internally)

    At any rate, if the dreaded head gasket is needed, the parts are not too bad and its not rocket science, its just a dedicated 5 hours of your life (or more without the tools, experience etc.

    Lastly the driving reason I joined to post this, and the part that anyone doing a google REALLY needs to read for the job:

    The most published rad removal procedures on the web are rubbish.

    The websites where a trusted expert weighs in were the worst, and it was apparent they were full of it 5 minutes after I poked under the hood.

    No, you do not remove the air box. No you do not remove the battery or tray (but you could unplug it to keep any and all fans off) and no you do not disconnect the AC lines or fuel lines or any of that happy horsesh*t. If the goal is to drive billable hours, I guess you do, but if the goal is to spend less time in the garage, then dont.

    1) Remove the plastic cruiser nose. 4 screw and 6 tabs, the 4 on the bottom of the sides push upwards, the 2 top sides ones downward. Child proof pill bottles are harder.

    2) remove the upper core support, 6 10mm hex head bolts and a 13mm to remove the hood latch thingy and the stupidly thin and worthless vertical support. (support for what? this thing is guaranteed to hole the AC core should you ever hit a bird or larger) Pull it up and off, favoring the passenger side first.

    At this point that radiator is essentially free. 10 minutes of your life is gone. In fact, you spent more time hunting up the 10mm socket.

    3) drop the hoses. undo the tranny cooler lines (if equipped.) Dont worry about the drain petcock., It is 100% sludged up as well and dropping the lower hose into a catch pan is faster and more satisfying

    4) using a 10MM socket (deep or short, depending on room) remove the 6 bolts that hold the fan assembly on, after unplugging the fan power. You will spend more time getting that red keeper out of the connector. They are also torx heads, but 10mm worked so I didnt size them up for torx.

    During this process note that the whole ac core/rad core/fan assembly can rock *forward* granting access for my 24 inch pythons, so you can get in too.

    Using not that much manipulation, you will be able to pull the fan assembly out, favoring the passenger side first and only a slight interference with the inlet neck on the rad.

    5) using same 10mm socket remove the remaining bolts that hold the rad core to the ac core. There is one speed nut that will fall to the ground.

    6) grab hold of the radiator and yank it out.

    Installation is the reverse AND note the valance goes on after you test everything and peek for leaks etc. AND by leaving this out, you can access the 10mm bleeder screw with no issues.

    Changing the thermostat: aka "do I really have to remove the intake?

    No. Merely unbolt the 5 or so 8mm upper to lower bolts and lift it 3 inches, it will move and nothing will break. If you want, insert the can of engine degreaser you bought between the upper and lower to hold it up. If you want to remove the egr tube in the back, I guess you can but it was an annoyance I didnt want to do the second time around.

    Now you can unbolt and bolt in the filler/thermo neck and remove it AND the hose as 1 piece from the passenger side AND when you need room to put in the new thermo and index the tab on the gasket, you can do it without magic. If you do this part while the radiator is out, its a complete non-issue.

    I left off some obvious stuff, like the rubber hood gasket, any plastic shields underneath etc. You dont me to lay that one out for you.

    Total time for removal, cleaning, installation, testing: 2 hours. Granted, this is not my first automotive rodeo and like Jeff Spicolis dad, I have a b*tching set of tools but a simple Sears Craftsman giftset and and a floor jack to get underneath should serve you well.

    So, to sum up, PR cruisers run cooler with the following:

    180* thermo with 2 small holes drilled
    complete and utter flushing and cleaning including hoses and tanks
    new radiator
    coolant change to that new 'compatible with everything of every color' coolant.
    and if you must use water, use distilled water.

    Ps: I promised a word about highways speeds. The speed limit is now pretty much 70mph on every highway. at 70mph this 5spd cruiser runs 3Krpm. This is not an old jetta with a digifant engine where it was built to do this. this is insane. 3K? wastes gas, builds heat, accelerates wear. At 2.4 liters in a large garden tractor sized vehicle this should cruise under 2800 (mebbe more like 2500) but alas, I call the motor the 'torqueless wonder' as it is. At any rate my b*tching aside, after a highway trip at the end of the exit ramp, if you have cooling issues, they will crop up HERE. watch for a temp spike.

    Adieu.
     
  4. ImperialCrown

    Level III Supporter

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    Welcome to Allpar. Be careful what you read into on the internet. There are a lot of 'myths' out there.
    The thermostat was likely removed by a previous owner who had an overheating issue and didn't want to fix it. The cooling capacity of the PT is fine if everything is working. The sludge may be stop leak in an attempt to hide a leak. You have to undo the mistakes made by the previous owner and diagnose the real problem.
    The radiator may be plugged. It may be beyond flushing and need replacement. The older PT used HOAT coolant. I don't think that they ever used OAT. Chrysler began using OAT in 2012.
    The head gasket may have failed. You may have the bubbles, but not necessarily the cream if the leak is from the combustion chamber into the water jacket. It doesn't have to leak into the motor oil.
    Testing for the presence of CO2 in the coolant is the best way to check for a head gasket combustion leak. Fresh coolant may not have accumulated enough CO2 to show a positive test result. With clean coolant, you may see bubbles. This is where you have to start.
    Diagnose first.
     
    Gerry G, Doug D and Bob Lincoln like this.
  5. Gerry G

    Gerry G Well-Known Member

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    Unfortunately is likely this is not the first time it has overheated and the head may be warped.
     
  6. pt006

    pt006 Active Member

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    My 2006 has never overheated. I rarely add coolant, maybe a cupful a year. I use MOPAR coolant only, but Zerex 07 may be substituted. NEVER mix HOAT with OAT. I believe all PT's use HOAT. Check your owners manual.

    There is a special procedure to get the air out of the system. Most PT cooling problems I've read about are due to a bad radiator fan motor or a bad radiator cap.
     
  7. dana44

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    The only cooling issues I have ever had with my 2 PT Cruisers was a slight leak of the thermostat housing itself, which just corroded and leaked a tiny amount, and have never had a problem with burping this setup at all. One major problem is an air leak with the overflow tube, where is sucks air instead of fluid, and people check the overflow and never pop the radiator cap (cold, of course) to make sure fluid is to the top of the radiator, then they start overheating. Also, as I have learned, the sensors and computer are set for a certain temperature to operate correctly. Going to a 180degree stat may be too cold for the computer and it might not like it. Carbs, different story, 160 works there, but certain temp is required on computer controlled engines, so I keep stock spec on that. Yes, one 1/8th inch hole drilled in the face is always a good thing to help purge air bubbles, and not large enough to keep the stat from functioning properly.
     
  8. Quaddriver

    Quaddriver New Member

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    Uh oh, you mean I have *not* been talking to french models? :)

    M whole purpose of posting the findings and procedures here (and soon to be on another site word for word) is I noticed as I said, the #1 complaint by far, was overheating. Where there is smoke there is fire, or at least coolant boil. I found what I found by google and what I found was so haphazard and plain wrong, I figure if some poor schlub can benefit from a google search 2 years from now...good karma.

    It was in 3 thrusts, first the problem. Magic bunnies and denial aint gonna work, the cruiser system is barely ok on a new one, which of course is *why* cooling is the number 1 issue. (chicken=>egg=>chicken) As for HOAT vs OAT, dont get confused by the names, its *still* an organic chemistry and is very reactive to fresh oxygen.

    For being a car that didnt exist before 2001, you would be right to take DC to task on why they used a 1970's coolant recovery system when *every*, not some, not most but EVERY other maker went to a 'more' sealed system on an organic coolant. All HOAT adds is the very same silicates that OAT removed...I guess they went full circle. (one of the internet myths is that mixing IAT with xOAT forms goo similar in nature to breast implants on french models....totally false) At any rate, dont drink any of them and use the universal stuff as I instructed unless some manu puts it plain exact english why you have to use their $30/qt bottle...

    Suffice to say, every cruiser would actually do BETTER with IAT, if change recommendations were followed. Like that would happen.

    But in case the mechanics are not well understood, if your cap is functioning and it pushes and pulls to/from this very very remote reservoir, each time it pushes, it displaces stale atmosphere and when it cools, replenishes with fresh oxygen. It may take a week, but the now contaminated reactive coolant will reenter the radiator. There is no gatekeeper. There is no avoidance. (its like the law of thermodynamics joke, you cannot win, you cannot lose, you cannot leave the game.)

    Fan operation was the first thing I checked. and why do radiator caps typically go bad? sludge from coolant plugs the vent passage that allows them to pass coolant back and forth.....(chicken=>egg=>chicken)


    At any rate, you can determine your (lack of) BTU recovery with a simple task.

    Either install a hyper accurate mechanical gauge or query the PCM. Determine your steady state, at speed temp on a given day. Then determine the temp rise you will get at a long stoplight. This is Delta-T. then calculate the implied airflow over the radiator, take the square area of the core times the feet/sec imputed velocity of the air based on vehicle speed. This will get you a CFM rating times some constant 'C' which will normalize the measurements to reality, taking into account shape factors, and will be different for every vehicle, but for this comparo can be dropped off. 'C' will be the same at idle, at speed, when towed etc so drop it.

    Then find the number of seconds it takes the coolant to return to T1 from T2 after the long stoplight when you get back to highway speed or whatever speed you used. This gives you degrees/second which can be fudged with to find BTU capacity. You *will* find, not might, not could, but WILL that the degree/sec rating of your PT will be a FRACTION of most other cars. Then again, most other cars dont have overheating as the #1 complaint...and those that do, I submit, will be similar. FWIW, its about 1/10th that of my monster block suburban. But that is designed to pull walmarts. Uphill. In summer.

    Im pretty sure this crude method will show you what you need, simply because it is based on what the manus actually do do, in the deserts of the USA during TTD (test to destruction)

    Anyways, the science aside, the 2nd part of my expose was the parts needed. I do not think the list is optional. I think the entire list of parts *AND* steps is as mandatory as the timing belt. Sorry. Blame DC. The owners at the time were more concerned with raping the company of cash and intellectual property than quality control or longevity. And the 3rd page of my post was simply because no accurate and/or straightforward R&R steps existed ANYWHERE to be found via google. When you have 'been in the biz' you learn how to take stuff apart in chunks or taking shortcuts, every bolt does not need removed unless as I said, the goal is to drive billable hours.

    It could be that no one cared to do any investigative work or even asked the question "why me lord?", dunno, my small contribution to society is my post (hey not long ago it was the bill of materials to rebuild the amp section on a kenwood KR4070 so I get around....)

    It may be the case that it was hurt in other ways and I have no real idea of the pedigree past carfax. It appears that my fix is spot on and no bad things are happening. If use and time dictate that in fact there is a head gasket issue, I will address it then, my kid would welcome the learning gig to yank the motor and re-seal/re-bearing it out of the car (far faster than a gasket install while in the car... In the meantime he likes his 'more-efficient-than-his-14mpg-4x4-truck' car and the fact that its a stick...it will serve him well as he heads to college. I got it for such a steal at auction Im way ahead of the game and rock auto is cheap and I dont have to pay for labor other than my aching back.
     
    ImperialCrown likes this.
  9. ImperialCrown

    Level III Supporter

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    There is a service manual with powertrain, transaxle, chassis and body electronic diagnostic procedure manuals in english on the oskin.ru website. It covers the export PT as well, so be sure that you are reading the correct procedure for what you have. The red text 'a' chapters in the table of contents cover the export vehicle differences:
    http://oskin.ru/pub/chrysler-dodge/manuals/Service Manuals/2001_PT_PTCruiser/
    It is free and that pays for itself right away. :)
     
  10. Quaddriver

    Quaddriver New Member

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    And it says to remove the AC lines and battery/tray ;-)
     
  11. ImperialCrown

    Level III Supporter

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    Because of the front end shape on the PT, the underhood is tight quarters from up top. Coming in from underneath and from the sides with the wheels off gives more room to work.
    Removing the battery & tray, air cleaner, cooling fan/shroud and plastic engine cover makes for more room from up top.
    Reclaiming and recharging the A/C would make the radiator replacement more difficult for the D-I-Y-er, unless you have access to or can rent A/C servicing tools.
    You may find a shortcut where you don't have to open the refrigerant system by tipping the condenser forward, removing the compressor to give some slack in the lines and room around the radiator?
     
  12. Quaddriver

    Quaddriver New Member

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    If you just remove the plastic nose piece and the upper support and that joke of a vertical support, you can rock the entire assembly, ac core, rad, fan forward 3-4 inches which makes more than enuf room to remove the fan assembly, after that a few additional bolts hold the rad to the ac core, remove them (all are conveniently the same size) the rad just lifts out. to get upper and lower fan bolts I just put her on the lift and go only high enuf to get the front wheels juuuuuust off the ground. if you are like 99% of the cruisers with auto trans, the two lines and the resulting bleed is extra fun but a catch pan will get it. I sold my own AC scavenging tools at carlisle last fall, but have access to some - its just a chore I dont really wanna do if I dont have to.
     

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