[cm961]

Hi All,

I'm about 40% done my head gasket replacement. So far I have everything torn apart, and one head removed. I plan to send the heads for machining if needed, but I'm hoping that won't be needed.

I will have some questions along the way but for now I'm wondering what else I should plan to do while everything is apart?

More details: The engine is said to have been rebuild about 64,000 km (40,000 miles) before I bought it, and I've probably put about 30,000 km (19,000 mile) since then totally maybe 100,000 km (60,000 miles). But I don't see how the head gasket could fail if the rebuild included that. I don't know much about engine internals yet but everything under the valve covers looks great, so I think some work was done there. The engine was very quiet and running great before the head gasket blew. I'd pulled over due to a smell I couldn't identify and shut off the car. When I turned it back on, crazy white smoke out the exhaust. We drove another 10 minutes before calling the tow truck. My temp gauge doesn't work so I don't know how hot it got. The mechanic didn't seem to think that would have damaged it (cracked block, etc.). I'll do a thorough check for cracks and flatness of the heads when it's fully apart. The mechanic confirmed with pressure test the rear head gasket. Coolant was pouring out the exhaust pipe when driving on/off the flatbed tow truck.

Does anyone know if a non-ac belt is available for the 3.3L and if so from where?

Thanks,
Pete

 

[ImperialCrown]

Follow the procedure in the service manual for best results. Head surface prep is very important for a successful repair. No scraping, 'sanding' or wire wheels. Only use a 3M Roloc bristle to prep the sealing surfaces. http://www.3m.com/product/information/Roloc-Bristle-Disc.html
Use a MLS (multi-layer steel) head gasket for best sealing results. See p. 142-143 here: http://oskin.ru/pub/chrysler-dodge/manuals/Service%20Manuals/2000_GS_Town&Country_Caravan_Voyager_Diagnostic_Diesel_Version_Incl/EGS_9.PDF
If a cylinder was pumping coolant out the exhaust, be prepared for worn rings/low compression in that cylinder.
I see a Dayco 980K6 serp belt listed for the 3.3L w/o air. http://autobeltsonline.com/dodge1992.html
Belt tensioners were also a common failure. The spring-loaded mechanism would bind up and belts could squeal and jump off.
I really wouldn't drive without a temperature gauge.

 

[dana44]

Agree with the temperature gauge, they help a lot.

How was the gas mileage before she blew the head gasket, any changes out of the blue prior to the gasket blowing?

With the head(s) off, do the valve colors look the same, with the exhaust being tan in color and the intakes being more of a powdered black color? Any discolorations in any of the edges or in one cylinder (it has been steam cleaned, so take that into account. What about the intake ports, all equal clean/black crud? Is that one cyinder port have a difference to it?

I ask these questions because a bigger problem with head gaskets and burned valves these days is due to a dirty injector. Rebuild everything and not take care of them can result in the same problem down the road.

 

[PCRMike]

These tend to be 200K+ motors. Something is not right here...

 

[cm961]

Thanks so much for the replies. You've been a great help already. I have the front removed. I can't figure out how to post pics, but the middle cylinder has a lot of black stuff built up on it (carbon?). Is that normal? I haven't got the rear head off. Going to do that now. I will provide answers to all the questions asked as I go along.

Thanks again, I really really appreciate the help.

Pete

 

[ImperialCrown]

Combustion colors are an important clue to the engine's health. Black is carbon build-up and some is normal. Overly clean pistons and combustion chambers can be a bad thing as coolant/raw fuel could have washed away the carbon.
Dry black carbon is usually left behind from burning fuel (maybe overly rich?) and wet oily carbon is from burnt motor oil (from worn/broken rings?).
Since one cylinder in this bank is like this and the other 2 aren't, some more investigation should be done. Any coolant pooled on top of the clean piston(s)?
See how the rear 3 cylinders look.

 

[cm961]

I've now removed the rear head and it is completely different from the front. The rears are all dry black carbon, pretty thick. The fronts are much more clean with just the middle one having some carbon build up on it. The busted head gasket turned out to be the front right cylinder #6 between the coolant hole as expected. It was fairly clean and has some coolant sitting on top of it. My only thought is that perhaps there was/is a fuel pressure drop between the rear fuel rail and the front which would put more fuel into the rear.

As for valves, the only one that looks different is the #6 that had the coolant in it. The exhaust valve is less tan, more black. As for intake ports, they are all blackish except for #6 as well which looks cleaner.

I'm starting to suspect that cylinder was firing too hot/lean.

I'd very recently done the gas tank, fuel lines. Fuel pressure tests were fine but maybe the front cylinders were all too lean for some reason. Could I have killed it from that? It certainly ran fine.

Pete

 

[dana44]

Was the tank replaced due to rust? If so, this damage could have been from dirty injectors. The computer and O2 sensor will make the injectors put more fuel into the system to correct a lean condition (caused from a plugged up injector), whereas #6 was not burning enough fuel, to make up for the unburned fuel/air going past the O2 sensor, the other cylinders were richened up to compensate, making them rich, thus black. Clean everything up, get the injectors cleaned or replaced, have the heads checked for warp, and a valve lap or valve grind might as well be done given it is taken apart, change the valve stem seals.

 

[cm961]

Indeed, the tank had rusted and was leaking at the seam. Also, when I initially installed it all I had the fuel lines reversed at the fuel rail. I'm thinking that may have crudded up the front three injectors. I'm going to send all 6 injectors for cleaning. The heads are in the shop now. I'm not sure exactly what they are doing but I told them to give it the full treatment.

Thanks again, all this advice is wonderful.

 

[cm961]

Heads are on and valve cover gaskets installed. I'm a little bit concerned about how the head bolts torqued on. I followed the procedure in the manual for the 2000 model year 3.3L. After the additional 1/4 turn on each bolt it says they should be over 90 ft. lbs (122 Nm), however some of them were not. It says to replace the bolt if they aren't but I used brand new bolts around. The only thing I can think of is that I did not run a thread chaser, I simply blew out of the holes and ran a bolt in and out until it came out clean. What opinion do you guys have here? Should I remove everything and do it again? I already have the valve covers installed but not much else. If I redo it do I need a new headgasket set?

Thanks,
Pete

 

[dana44]

I would suggest redoing the torque on the bolts given it hasn't been started yet. No, you don't have to replace the head gaskets, they haven't been heated. Sometimes it is necessary to torque the bolts, back them off, then torque them again, then do the 90 degree extra (quarter turn). Is there anything that said to add like a drop or two (no more) of oil onto the threads so they run in smoothly? Highly recommended either way. There may have been something in the threads, a burr somewhere on a thread, or the pins holding the head in alignment may have caught up just a hair. It can happen.

 

[cm961]

ok thanks. I've taken apart the front head and re-torqued the bolts. Same thing on the first couple. With the torque wrench set to 90 ft lbs the bolts still turn after doing the additional 1/4 turn procedure. Perhaps my 1/4 turn is off. It's pretty hefty work even with a breaker bar. I'm starting to think these head bolts I got off ebay might be as new as they were said to be. The threads check out but I don't know how to test for a stretched bolt since the picture in the FSM isn't clear to me. They certainly look fine. I'm not sure what to do.

 

[dana44]

OK, let's go over a couple steps to ensure there is equal pressure on the head and the bolts using the proper bolt tightening sequence, usually center top to bottom, then left two, then right two, back and forth. Follow the book for the proper sequence, it is important.

Do all the bolts at 40lb-ft, then go around and do them at 60lb-ft, then 80lb-ft, then 90lb-ft twice (it verifies the torque), then do the same proper sequence to quarter turn more. There is the chance you can get more torque out of the bolts if you want, but this way guarantees they are torqued all equal and any kind of stretching done properly , not catching on anything, like a burr or threads having junk in them.

 

[cm961]

Thanks so much for the help. Are you saying torque to 90 ft. lb then add 1/4 turn? FSM says do it to 65 ft. lbs. and then a 1/4 turn. After that they "should" be tighter than 90 ft. lb. I played with it for a few hours and finally settled on all bolts checking out to 85 ft. lbs. I've definitely got the sequence stamped on my brain now, and my arm is very sore.

 

[cm961]

Well this bad dream just turned into a nightmare. I just snapped bolt #5 off in the block on the rear side with the torque wrench set to 75 ft. lbs. My plan was to take them all up close to 90 ft. lbs., then back them down, bring them to 65 and then add the 1/4 turn. I don't think my wrench failed or anything because it wasn't very difficult to turn. I'll call the machine shop tomorrow but I'm going to assume the block will need to come out to fix this unless there's some other way to get a broken bolt out.

Was my major mistake not running a thread chase or tap down the holes? I don't know. I'm defeated.

 

[dana44]

No, sorry, mistake on my part of what you were saying. So it is 65lb-ft then quarter turn.

Go 30, 50, 65lb-ft, then quarter turn. nice even pressure this way, and let them sit where they are whatever the setting is.

What they are doing with torque to yield bolts is taking a set pressure to squish the head gasket, then the extra quarter turn is a fixed extra amount of pressure. Stick with me, it takes a bit to describe.

There are (I believe) 16 threads per inch on the bolt. That makes each turn of the bolt .0625 for each turn of the bolt one full turn. and .015625 for each quarter of a turn, so roughly fifteen thousandths of an inch extra squish on the head gasket is done after the torque even pressure if placed on the head gasket, which is usually pretty good to prevent head gasket failure of aluminum to cast iron block. As long as the torque is done nice and smooth to begin with, they are usually pretty reliable.

 

[cm961]

I had an encouraging discussion with the local engine rebuilder. They seem to think I will be able to get the stuck bolt out. I've ordered a new bolt set. I do not trust the bolts I've got off ebay. Should I order a new gasket as well? It's been tightened down and released a number of times and now I've removed it completely. It seems to have oil on it. Is that normal? Perhaps thats what is causing my issues?

 

[dana44]

I also missed the snapped bolt and the torqueing to 90lb-ft then backing them off, that is not recommended at all, must have posted the same time I was. There may have been some oil in a bolt hole, but I guess glad you got new bolts, again, but one of two things. Wipe the block, head and gasket with laquer thinner or other degreaser to clean them off, but if you do want to replace the head gaskets after all this fun, do so, won't be wasted money, just good insurance.

 

[cm961]

Will do. I ordered new gaskets just in case and new bolts. Will be redoing front and back. Also ordered the right tap so I can clean out the block threads. I'm going away for a week or so while the parts ship, so I'll pick this back up in early August. Thanks again.

 

[CudaPete]

Get a left handed drill bit. The broken bolt will spin right out.