[warlord]

what do you suppose it means if the car drives normally and the temp guage raises and lowers like usual, but the heat is only luke warm, and when i turn the car off after a drive the coolant boils and some squirts out of the cap for about 2 seconds?

 

[Bob ONeill]

Thermostat not opening or not opening all the way. Or, what's the chance the water pump isn't turning?

If you don't have heat inside the car yet the coolant is hot then it's not flowing. If the water pump(belt) is OK then it's not allowed to exit the head and when you open the cap it back flows from the expanded coolant in the head through the radiator (bottom hose) and up and out.

 

[Bob Lincoln]

We'll need a little more info. Describe the range of up and down tempeature swings - warm, 1/3 scale, 1/2, 2/3 - and how rapld the swing is, and how often it happens. For a Daytona with unobstructed radiator and heater core, and everything in good condition, it should not go above the halfway mark except in desert heat while idling. Normally it should be in the 1/3 to 1/2 scale range.

You might have a plugged heater core. That won't account for the coolant leaking at the radiator cap, though.

Has the system been serviced recently? A trapped air bubble can cause lukewarm heat and uneven gauge swings.

Also, are all of the hoses hot to the touch when the car is warmed up? One heater hose should be VERY hot, the other reasonably hot, after a drive. Top radiator hose should be hot all along its length.

If the radiator cap squirts out coolant, that means that the pressure has exceeded its 16 psi relief rating, or the cap is defective, or the overflow line to the jug has plugged. It can also mean a failing head gasket, whereby there is a compression leak between a cylinder and a coolant jacket, and the running engine is pumping exhaust gas into the coolant. This will show up at cold idle with the radiator cap off, as a steady bubbling at the top of the radiator.

Does it still idle smoothly? Is there any smoke out the back? Are you running a 50/50 mix of antifreeze and water? Is it a 195F thermostat in the engine?

 

[warlord]

well its 20 degrees out here at night and once the engine warms up i start to get warm air from the vents so i am believing the the pump is pumping.

the guage gets to about 2/3 then the fan comes on and cools it down to about 1/3 - 1/2 it has always been that way.

idle is smooth once thigs are warmed up a bit

havent thought to touch any hoses and it was tool cold outside to really do much of any diagnostic at 4am.

yes coolant is 50/50


i think i would like to explore the recent service pathway here since ive had the entire airbox out of the car to fix the doors and flaps inside and i just reconnected everything without any real thought on air bubbles. so at the time of reconnection the entire heater core was filled with air

 

[Bob Lincoln]

OK, you need to park the car uphill and, with engine cold, remove the radiator cap and idle the car with heater on full until the car warms up. It should be enough of a slope that the radiator cap is higher than the thermostat housing. If there are bubbles, they will rise to the highest point (radiator opening) and burp out. Be prepared to top off the coolant in both the radiator and the overflow jug. If the coolant just rises to the top without bubbling when warm, put the cap on and drive it. It may still burp more after a few cycles of warming up and cooling, so check the level daily. I went through this recently, it took more effort than usual to burp it. Now the heat is sufficient, and the temp gauge does not go over the halfway mark even at hot idle.

 

[TurboPacifica]

CudaPete told me to squeeze release and squeeze again the upper hose with the cap off and engine running.
This sucked in the fluid and I hadn't had a heating or overheating problem sience.

I had just replaced both hoses and the thermostat.
To help the car run cooler.

 

[warlord]

well I was about to fill the system i go to start it and the starter has died so that will be a delay

 

[bguy]

Problem with these engines (2.2/5) is that air gets trapped in the water box around the thermostat, which prevents the coolant from warming up the pellet and delays the opening. There should be a plug next to the thermostat to let the air bleed out.

 

[Bob Lincoln]

Yes, but you can never get the plug out. I tried on a new car that I bought once, one week old, and it would not budge with 1/2" drive socket, just rounded it out. That's why you park it uphill to burp it. I put a Stant Super Stat thermostat in last year, and have never had one of these engines warm up so fast. On a 25 degree day, it now reaches fully warm after 2 1/2 miles of driving. Used to be 3 1/2 to 4 miles.

 

[Doug D]

The problem with the "plug" is the housing is aluminum alloy and the plug is steel. In very short period of time the plug becomes frozen to the housing and becomes impossible to loosen and remove. I've had three 2.5 engines and all of them had the plug completely "frozen".

One way to ensure air can't get trapped in the housing is to drill a hole in the flat surface of the thermostat using a 1/16 drill bit. When installing the thermostat make sure the "hole" is at the 12 O'clock position. The hole will allow any air to escape to the radiator and be cburped out. Yes, some coolant will flow through, but it's not a significant amount.

Here's another trick I've hard of, but never tried so I can't vouch for it completely. Now if you happen to not live near hills or have a pair of ramps, another trick is to insert an aspirin tablet to keep open the thermostat slightly. Eventually the tablet will dissolve, but by that time any trapped air should have been able to burp out.

The 2.2/2.5's suffer from the thermostat housing as the highest point of the cooling system - that's why air tends to get trapped there.

 

[Bob Lincoln]

But no need to drill that hole if you park uphill and wait for the thermostat to open. I've never had to drill one.

 

[Doug D]

All I can tell you is it worked for me.

 

[Bob Lincoln]

Sure, it works; I'm just saying it's not necessary to drill it if you burp it by parking uphill.