QuestionQUESTION: Hello Ray, it's me scott, with the '90 lebaron conv that has no heat. As you know sir, I changed the thermostat already and did make use of the breather screw on top of the thermo housing. I also tried one other thing...I completely flushed out the cooling system and started fresh. I finally got heat again, but only for about 20min. or so; then my temp guage shot right back up to "H" and the air and guage keep changing from warm air to cold and back to warm, then cold, and so on. Not to mention I have gone thru about a gallon and 1/2 of coolant trying to "burp" the raddy. Is there something I may be overlooking with this impossible car of mine??? Maybe a sensor or something??? Besides the fact that it's being a typical Chrysler product, any ideas what I do now???
ANSWER: Hi Scott,
The oscillation is normal if it runs from about 1/4-3/4 of scale; that is the action of the thermostat opening and closing. But it shouldn't go to H and back to C, etc. Do you get boil over or loss of coolant when it goes to H, or does it just get to H and then shoot to C without loss of coolant?
What is the fan doing? Does it come on when it is moving to H, and go off when it drops below about 1/2 scale? That fan action is controlled by the coolant temp sensor which is a different sensor than the temp sensor for the gauge.
When do you lose coolant in the cycle, and have you lost it all due to boil over?
Are you loosing coolant from the tailpipe: do you see a lot of white smoke coming from it when you start the engine from cold? If so, does it smell of coolant if you let it condense on you hand?
If you start the car from cold, do you hear any bubbling going on if you let it warm up at idle, if so, is the sound coming from the engine proper?
It could one of several possibiities, so tell me the answer to those questions.
Unfortunately I have to be unable to take questions for the rest of the day, but I will be available early tomorrow, so let me know then and we'll go from there.
Roland
---------- FOLLOW-UP ----------
QUESTION: Hi Roland, just as an FYI, in the subject box you had a '93 3.0L mine is a '90 2.5L 4cyl lebaron. Anyway, I'll try to answer your questions as best as I can. YES, there is a loss of coolant from boil over...into and out of the overflow tank. YES, the fan does come on and shuts off when it should according to the guage. NO, I have not lost any from the tailpipe, no weird smell or sticky sweet white smoke from the tailpipe other than normal cold weather exhaust smoke. The only bubbling is from the radiator gurgling as it's warming up at idle, and continues to do so after about 10-20 min. of idling; that's why I kept adding cooling in an attempt to "burp" it. I truly hope these answers have helped you with this. Thank You VERY much for your time thusfar. Scott
AnswerHi Scott,
Sorry for the mis-identification of which engine you have. To begin I have found your original December question pasted it in (my answer follows):
HISTORY
HI, I have a 1990 lebaron conv that just suddenly stop blowing ANY warm air,let alone hot. The temp. guage instantly within seconds shot up to "H" and all that came from the vents was ice cold air. I changed the thermostat and did get hot air for a few minutes, temp guage stayed in normal range. Unfortunately, that only lasted while the car was running. Later that same day, I went to run an errand and I'm back to square one...temp all the way up and ice cold air again; even after letting it run for about 20 min. or so. There is no wet floor on the passenger side or any antifreeze "smog" filling up the car, which is usually sure signs of a heater core problem. Totally lost at this point, any ideas??? PLEASE HELP!!!!
Answer: Hi Scott,
With a temp gauge shooting up to H I would suspect that you are loosing coolant into the compression chambers due to a head gasket leak. Check for whether the oil is foamy or whether you get execessive white smoke out the tail pipe when you first start the engine from cold. If so, that would be symptomatic of such a leak. Also, if you hear bubbling early after you start, coming from the engine, that is another sign or early pressurization of the radiator(remove radiator cap after a minute or so of idling carefully). It should not be pressurized that quickly. Have you also run out of coolant, perhaps?
Until you get the engine cooling system up to snuff you won't get any water circulating to the heater core. Let me know what you learn and also tell me which engine you have.
Roland
Hi Roland,there's a few things that you wanted me to check and let you know. Yes there's some white smoke when it 1st starts but it disappears quickly,then again; it is only in the teens for a temp. I haven't really noticed any "foamy" type oil, as for the bubbling and loss of coolant...once the car has been running for approx.3-5 min. the coolant does boil over into the overflow tank,which in turn gets too full and runs out the overflows' spout. Can you please tell me,if you can; how is it that I got warm to hot air right after changing the thermostat?? But,shortly after on that same day; the temp guage went up to "H" and all I got was ice cold air. The old thermostat by the way was stuck with the spring compressed when I took it out. As for the engine it's a 1990 LeBaron conv. 2.5L non-turbo 4cyl. As for the mileage, the odometer was frozen since I bought it 2yrs ago and my best guess on it would have to be somewhere at 235k to 265k miles. As much as I hate to hear it, if it turns out to be a head gasket issue that's big $$$ isn't it??? And is it possible for the DIY selfer to do??? My only income is from disability and I can't do a whole lot to get it fixed. Well...hope this info helps us both.
Hi Scott,
A ha! Now that you tell me you have the 2.5L engine I have an idea for you. That engine block has a box which holds the thermostat as you already know. But you may not know that you have to refill the system after you have drained it down in a particular way. You will notice that the box has a plug on the top that is removed with an 8mm Allen wrench. So starting with enough coolant drained so as to get the level in the system down below the box (a couple of quarts from the radiator drain plug collected for reuse), then you remove the plug and then start to refill it via the radiator opening until the level of coolant raises to fill the box and bring the level right up to the very top of the opening. Then you lube the threads on the plug with a little grease/oil and put it back in. Then you fill the radiator to about an inch below the opening, put on the radiator cap. Then add coolant to the overflow bottle to the 'cold' line. Then start it up and see how she runs.
If you didn't do that you have air trapped in the box such that thermostat won't open properly and coolant can't flow. I'll keep my fingers crossed that everything is alright with the balance of the system.
I did the head gasket on my 2.5 quite successfully if it needs to be done and I can send you the step-by=step instructions.
Roland
End of HISTORY
Now, in response to your Follow-up observations and questions:
It still sounds to me like there is air in the thermostat box, so begin by rechecking for that by lowering the level in the system to be less than that of the top of the box (about a quart will do via the radiator drain cock, and also before you even start draining, start the engine and put it on 'heat' position at the control panel then turn off engine so as to be sure that the heater pathway is open to be drained as well) then refill via the radiator to the very top of box, put on box plug, refill the rest of the system via the radiator cap opening.
See if that stops the boiling over as you warm it up from idle.
If not, then I would wonder if your water pump impeller is loose on the shaft OR if you have a small head gasket leak. The bubbling early-on makes me suspect the gasket. That could be detected by a muffler shop that has an exhaust gas detector which they could put on the radiator cap opening to see if they can detect any exhaust gas in the cooling system. If it passess that test, and you are sure of no air in the thermostat box, and that the radiator core is open and flowing well, that leaves the pump as about the only other explanation and thus that I would suggest that you try replacing.
It is possible that the replacement thermostat is 'off-value' from what the box stated, so although it is re-doing the job you could consider removing it and testing it in a pan of heated water and by means of a thermometer verifying at what temp it begins to open, which should be about 193 F. But the wide variation in heat output to the cabin suggests you have an inadequate flow of coolant to the heater core which could be due to exhaust gas air in the heater core blocking the flow or to inadequate water pump action.
I wish I had a simple definitive answer for you.
By the way, I just had a similar situation with my '89 2.5 non-turbo where the gauge was running very close to H but never boiled over. It went high pretty fast but was oscillating up and down in the high range so I knew it was working and I was getting steady heat. It was an old thermostat so I replaced it and it is now running in the 1/2-3/4 range instead of the 3/4-15/16 range. That is not the same as your present problem, of course.
Roland
