QuestionI have a 2000 Chrysler LHS,3.5L,with overheating issues. Started about 2 months ago with intermittently getting hot. Refilled coolant and continued. About 2 weeks ago, chronic overheating. Each time there would appear to be need for more coolant in which we thought was due to overboiling. It was parked to cool before redline each time, added more coolant, eased on home after cooled off. We searched for fluid leak and found the radiator to be cracked. Replaced it, under warranty luckily (water pump, radiator, timing belt, and T-stat all done 2-1/2 yrs ago), refilled coolant, still hot. Replaced water pump. Still hot. Found heater hose with a split, replaced it. Still hot. Checked T-stat in boiling water, all worked well. Still hot. So we pulled out the T-stat and left it out just desperate for it to quit getting hot. This did no good. We did turn on the heater, attempt to get all the air out of the lines, fill with coolant, etc. The car will get hot after about 20 mins of idling and/or driving. The coolant will start boiling by the time the temp gauge reaches the halfway mark. Both fans work well and kick on and kick on higher gear also. There is no coolant in the oil, no oil in the coolant. Motor runs great, sounds great, full power, no missing, nothing. No steam or water from tailpipes. No evidence at all of a gasket or head. When we attempted to bleed the lines, I took of the reservoir lid, opened the bleeder, cranked the car with heater full blast. We continued to get what appeared to be air out of the line and was still doing this up until the point the coolant got so hot it again started boiling so it was boiling and popping up and out the reservoir tank. So I turned the car off. Should I have put the cap back on the reservoir tank and continued on?
Does the 20-min period of time before getting to the point of overheating fall into the typical head or gasket syndrome? I can drive to town, go to grocery store, leave and come home and car be okay as long as I am not out and about running it longer than 20-30 mins max before it gets the chance to cool back down.
There appears to be a lot of pressure, not sure how much is normal. We have now had a busted radiator, busted heater hose, and now a pin-size hole in the reservoir tank also. Not sure what is cause and which is affect but wondering if they aren't all busting due to the pressure but no idea what was the beginning of the overheating cause either. So far, we have replaced radiator and water pump and heater hose, removed T-stat.
When it gets to boiling with the reservoir cap off, the coolant will start popping out and there will be some steam. I assumed this was just from the extreme heat but is it possibly the over pressure from the heads or gasket?
I know it is likely the heater core is out as I have no heat & haven't for a while but the car still runs hot even without the AC or heater on. Would the heater core being out make it overheat this much without turning on the heater and/or AC? I thought the coolant only circulated through the core when the heater was turned on.
Also, the transmission oil cooler was removed at the time of all the repairs 2 yrs ago. It has been fine with no issues up to this point. You think its possible that could be the cause of my issues now? Temps are in the 100s here.
Thanks for your time with my lengthy info and questions. I've researched and read so much looking for answers but I am still stuck. Hubby says head gasket most likely but I am not convinced yet because I don't want it to be that and we were so very careful about shutting the car down when it got close to the red mark."
AnswerHi Lorrie,
Thanks for the very detailed history. A number of possibilities come to mind. The head gasket leak as you mentioned can result in oil in the coolant, coolant in the oil/crankcase, or coolant out the tail pipe as white smoke when first starting the car from cold after a hot shut down.
It can also be detected by there being exhaust gas detected in the air coming up into the reservoir and for that you would need to take it to a radiator shop that has an exhaust gas detector. Also, if you hear bubbling sounds early after starting the engine and before the gauge gets into the mid-range, that would be a sign of a head gasket leak. The white smoke at start up might not be so noticeable in summer, but still look for that in the first few minutes of idling it at the curb early in the day when it is still cool. You might check for the early build-up of pressure at the reservoir cap opening as a simple test for pressurization due to a head gasket leak. Open the cap early on to see if hear the release of pressure.
The coolant normally always flows through the heater core, but unless you ask for heat (sending cabin air over the heater core) the heater core doesn't dissipate very much of the heat in the coolant that passes through it. You could check the temp of the two hoses that go through the firewall to the heater core to determine if you do or don't have flow through the core. The hoses should be similarly hot; if one is decidedly cooler than the flow is obstructed.
Then there is the question of air in the system. Have you used the bleeder valve/nipple on the front of the engine to pass out coolant/air and squeeze the upper radiator hose as a means of removing air from the system. If not try that. Put a length of 1/4" hose on the nipple and run the engine while collecting out the hose and back into the reservoir bottle until you believe all the air is out of the system that way.
How about the reservoir? Are you only filling the side that is supposed to be filled to the line while the return side from the engine is empty? You have to not fill both subsections of that bottle. And of courst the lid is the pressure cap so any time you run with that ajar/off the system won't pressurize and so you will get boiling at much lower temp than otherwise. The fact that you get boiling off before the gauge gets to 1/2 raises the question of whether the cap for the reservoir is not holding pressure and therefor should be replaced.
It is possible that there is an internal passageway in the engine that is obstructed and causing local hotspots in the engine, but that is not typical of the 3.5L.
I don't believe the trans cooler would be involved with the coolant system issue. But it would be better for the life of the trans to have that cooler.
If you don't have the instructions from the manual about refilling and bleeding off the system, I can attach those to an email by copying them off a CD that I have of the '04 manual which is identical to those for an '00 model. Send me a 'private' option follow-up question wherein you tell me your email address (normally the Allexperts site doesn't tell us email of the questioners). Be sure to use the 'private' of the address will be deleted.
It may be the case that the temperature gauge is inaccurate, but the fact that you are loosing coolant (but it appears that we are certain how) suggests that it is getting too hot.
You might also use the ignition key for fault code readout:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the odometer to see in place of the mileage a 4-digit number preceded by a P might appear which would be a fault code that might be relevant to this problem.
Roland
