Chrysler Kcar thermostat replaced-burp out the air

[tomlct]

Does anyone remember these? My 1988 Aries - 2 weeks ago, temp gauge shot way up, I pulled into a parking lot to cool, it dropped on its own, so I was able to make it home without overheating. I already had a new t-stat & outlet & gasket. The thing with that setup (2.5 L, also the 2.2's) is that the radiator is lower than the block. The t-stat housing is in the water box casting. There are 3 holes in it - top is bleed plug, side has a plug (on this engine), and the coolant temp sensor is the lowest hole. I sprayed lots of PB Blaster all over the plugs & left it for a week, but as I feared, I could not remove the proper bleed plug or the other one. Used 8 mm Allen socket & breaker bar, no luck, the hex hole rounded off. So I loosened the coolant temp sensor, and let some of the hot coolant spit out of it while the engine was running. I also parked it on ramps, so that the radiator would be higher than the engine and ran it until hot, with the cap off. So far, it seems good - temp gauge steady, and a bit lower than before, and I think the fan hardly goes on now.
A couple of things, asking for comment -
1. The hole in the water box for the coolant temp sensor is not at the high point of the water box - would that make it less effective in forcing out the trapped air?
2. Does parking it on ramps and raising the front of the car sound like it would work? I think it does.
3. I read another option for this - has anyone had to do this? - Drill a small (like 1/8 inch) hole through the new t-stat body, so that any trapped air will slip past and into the radiator and then go out into the overflow and be gone.

 

[michaelluscher]

Spill free funnel to bleed the cooling system

EPAuto Spill-Proof Radiator Coolant Filling Funnel Kit https://www.amazon.com/dp/B01I40ZQWE/ref=cm_sw_r_cp_apa_ua-jybJ39RZ2H

That's the cheapest way to buy it, and here's a video on how to use it

 

[Ojustracing]

Originally Posted By: tomlct
Does anyone remember these?
1. The hole in the water box for the coolant temp sensor is not at the high point of the water box - would that make it less effective in forcing out the trapped air?
2. Does parking it on ramps and raising the front of the car sound like it would work? I think it does.
3. I read another option for this - has anyone had to do this? - Drill a small (like 1/8 inch) hole through the new t-stat body, so that any trapped air will slip past and into the radiator and then go out into the overflow and be gone.


Ahh the good old days. I used to drill a bleed hole back in the day. These cars do not like being hot at all. Head gasket cracked head issues.

 

[sprite1741]

Hate to say this but a blown head gasket causes the overheating. It's really a common design problem with these engines. They all do it eventually. I am on my 3rd head gasket. It's an easy DIY job, a shop will be too expensive. I got my gaskets off ebay, head and valve cover for $20, oil and coolant locally. Takes around 5 hours on mine but it's a turbo, yours should take less time. I would remove the hex head at the top, I always need to bleed that. Drill it out if you have to and retap for a new bolt if necessary. You can drill a 1/16 hole in the top of the thermostat and reinstall it so the hole is at the top will help bleed out trapped air for a while or it will overheat again until you get a new head gasket. It will get worse. the last time on mine it dumped coolant into the oil, the other two times it was exhaust into the coolant. Really a routine job with these. I did my last one almost 1 year ago. Unless you ran it overheated for a while your head should be fine. Mark all your timing spots before removing the head, but if you forget these are really easy to set the timing. Mark the TDC 0 deg mark on the flywheel with paint. Chrysler puts half and quarter marks on as well and you can get the wrong one if your not careful.

 

[92saturnsl2]

Man do I remember these. The 2.2/2.5L K car engines. If I won the lottery today, I'd buy a Plymouth Reliant and make a turboed sleeper out of it. I grew up riding in these cars.

That said, the head gasket is a common problem. Where most engines have a water pump failure, these just happen to have a head gasket go. Rather poor design, no way around it. But do check to make sure it's not something simple.

Drilling the thermostat is a proven way to bleed air from the system, but you want a small hole, 1/16 to 1/8" at most, otherwise you'll have slow warm-up in the winter. I used to drill 1/8" holes in the thermostats on GM 3800 engines, which were especially hard to bleed, with great results.

 

[dishdude]

These are pretty easy to bleed, but as mentioned if you can't take the hex nut out drilling a hole in the thermostat is a good option. Before they added TBI to the engine, that hex plug was used for a sensor or carb warming circuit...can't remember.

These weren't any harder on head gaskets than other 4 cyls of the time, and if you are lucky, you can sneak by just sliding a new gasket under the head without taking the entire thing apart thanks to the one sided manifold design.

 

[redbone3]

I blew up several Opel water pumps before I learned the trick of drilling a hole in the thermostat.

 

[Lubener]

I had a 2.5 for ten years. I always used an OEM thermostat. I then drilled a 1/16 inch hole on the outer flange portion of the stat to allow any air to be belched out on its own. Position the hole at 12 oclock.You could raise the front of the car up high with the cap off, engine running to expel any air but you have to do it for a while after the stat opens. Good luck removing the bleeder plug, I never could and wound up rounding the hex. If you got it hot enough you could have spent the head gasket. I would pressure test the cooling system to make sure the H.G. isn't blown.I was fortunate to have the original head gasket at 180k when I got rid of the car last year.

 

[sprite1741]

The turbo is a little harder on head gaskets than the NA so maybe you can get by for a little while with just keeping the air lock at bay. The air build up at the t-stat comes from the head gasket leak. That causes an air lock which will overheat the engine very quick. The 1/16th bleeder hole will help to get it out, but does not fix the problem. If you overheat it again for too long it can damage the head. You should check the water pump, but I am still on my original 1986 one. The head gaskets all crack in the same place #1 cyl. by the bolt hole. This is my last one:

 

[Lubener]

Originally Posted By: sprite1741
The turbo is a little harder on head gaskets than the NA so maybe you can get by for a little while with just keeping the air lock at bay. The air build up at the t-stat comes from the head gasket leak. That causes an air lock which will overheat the engine very quick. The 1/16th bleeder hole will help to get it out, but does not fix the problem. If you overheat it again for too long it can damage the head.


If the head gasket is bad and combustion gasses are entering the cooling system , he would push coolant out forcefully and fill up the overflow bottle, maybe overflowing it.. Trapped Air after servicing cannot bleed out because the thermostat housing is high on those engines. He should pressure test the cooling system and do a compression/ leakdown test to verify head and or head gasket issues.It overheated for a reason, providing the fan is working.

 

[tomlct]

Thank you to all for the replies. Later today, I plan to buy a few good drill bit sets and drill a 1/16 inch hole in this t-stat (I could imagine breaking a bit that thin, so I want to start with > 1). I don't use the car in the winter, but it will be interesting to do a compression /leak down test and pressure test the cooling system, maybe in the spring, after I buy some decent tools for this. I had a '91 Acclaim where the overheating was caused by a head gasket, and we got away with just replacing the HG, but that car had around 160K miles when it happened. On this one, the water pump was replaced last year, along with the original timing belt (mileage is now only 104K). This t-stat was also original. I am hoping the tests will show things are still tight, and maybe that t-stat just mechanically got stuck in the closed position, but we will see, I guess. When it happened, I was backing into a parking space, in case I had to be towed, on level ground, and all of a sudden, the gauge just dropped. The fan works OK - it always came on when needed, and will come on with the A/C, and came on when I had unplugged the coolant temp sensor. I was thinking of spinning it loose for the air bleed. I ended up plugging it in with the sensor almost out of the threads, and then let the coolant out, while it was running.

And as an old Opel guy (a '70 Kadett, a '74 Manta, and a '75 1900 (which made it to almost 200K miles and still ran pretty well)) - I replaced the water pump 3 times on that one, in those 200K miles. As I remember, 2 of them because of leaking, and 1 just seized on a very hot summer afternoon, along I-95. I just pulled off the road and loosened the alternator to remove the belt, and drove for around 10 more minutes with no water pump. The gauge went up but not to the max, and I used the car for maybe 7-8 more years after that. Oh, the days of cast iron heads & cast iron blocks.

 

[NHGUY]

Drill the hole,maybe use a vacuum pump on the radiator,run engine without cap to burp.....and use a Cometic MLS head gasket like I did.Future head gasket problems solved...

 

[NHGUY]

Welcome to the club....of 88 Aries owners! lol

 

[eljefino]

Just checking in... I had a 91 dodge dakota 2.5 with a marginal head gasket. Just drove it to the dump 1000 miles a year and limped it for a couple years. Had bubbles in the rad overflow tank but no other symptoms.

I wasn't much of a mechanic then so I bought a dodge spirit for $160 with a horrendously blown gasket, white smoke out the back, etc but no coolant in the oil. "Practiced" on that. The first symptom, most of the time, is exhaust in your coolant and so you get a pocket of it behind the thermostat so the next time the car starts up there isn't any hot coolant to "tickle" the pellet and make it work. So you get to a point where it's steam doing the job and the t-stat slams open and lets a slug of cold water come in from the radiator all at once, which is more thermal stress, which abrades the gasket that much faster.

A hole in your thermostat will prophylactically prevent this in future. Even a "normal" t-stat opening event will be tempered with a little built-in bypass. And the coolant flow around the pellet will be better with some of it escaping through the hole.

A 1/8 hole will give you plenty of heat. Maybe 15 seconds later than otherwise, but who cares.

PS the spirit went together like gangbusters and I transferred my experience to the dakota that also worked mint. I used zip ties and a bungee cord to the hood to hold the top of the timing belt to the sprocket and keep tension on the bottom crank, which I didn't even open up.

 

[tomlct]

I have drilled a 1/16 hole, and then back up on the ramps for around 1/2 hour, squeezing the lower hose a bunch of times. I think I saw some bubbles. It went through a fan on/fan off cycle. The results of a pressure test and compression/leak down test will be interesting, when I can get to that. Fingers crossed.

 

[Bgallagher]

Oh man, we had the exact same car as a shop car when I was in HS. I swear I could fix just about anything on that car with my eyes closed. That and the 85 Ford Tempo.

As mentioned before, drill a small hole.

 

[Oldmoparguy1]

Little known fact, the thermostat for the early 3.3 L V6 will fit and comes with a small vent hole and a check ball. Works very well. On some heads it requires a little filing of casting flash, but otherwise fits.

If you still have bubbles in the rad, then you most likely have a blown HG. It usually goes at the back stud on #1 cylinder. Feel free to PM me, I have many years of experience with that I4 motor.

 

[tomlct]

Thank you. I will take it out tomorrow morning. Last Sunday I went out for around 1/2 hour & the temp was fine. I would love to drive it to work occasionally, but now, I would be driving in the dark in both directions, heavy, aggressive traffic, etc - so weekends only until it snows, and then nothing until spring. When I retire (1 more year), if it stays OK until then, I might want to try this repair myself. I guess if I think I am going to do this, I should start to soak the manifold studs and that round exhaust joint with something like PB Blaster.
Can that early 3.3 t-stat be found with a 195 degree rating? That is what the original one was and what I have used now.

 

[Lubener]

Originally Posted By: Oldmoparguy1
Little known fact, the thermostat for the early 3.3 L V6 will fit and comes with a small vent hole and a check ball. Works very well. On some heads it requires a little filing of casting flash, but otherwise fits.

If you still have bubbles in the rad, then you most likely have a blown HG. It usually goes at the back stud on #1 cylinder. Feel free to PM me, I have many years of experience with that I4 motor.


It's easier to drill the vent hole in the stat and accomplish the same thing, why start filing the head to make that stat fit? Aluminum filings falling in the water jacket...Doesn't make sense to me.

 

[sprite1741]

The small hole in the t-stat allows combustion leaks from the head gasket to get past the stat and prevent overheating from an air lock. You can drive it for a while but that that leak will get worse. It will eventually dump coolant into the cylinder and or the oil. You won't be driving it long after that happens. If you see white smoke behind you or the oil is looking milky, stop driving it.