When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I searched pretty extensively and couldn't find anything directly similar.
I will try and keep this as short as possible.
Ever since I have had the car (2ish years) my in car heat has been hit or miss. Some days it will blow warm other days it will only blow warm while under load. To this day I have the same issue.
About a month ago had an overheating issue. Temp spiked one day to about 2/3rd on the temp gauge. Immediately turned off and put in a new water pump, thermostat, and rad cap. Issue solved. Drove 1k miles on the car no issues no temp change or fluctuation.
Last night after driving on the highway for about an hour my temp started to creep up. Pulled over let it cool down check coolant a little low but nothing crazy. Topped up started up drove for about 10 minutes and temp creeped up again. Took it to a shop they found a small pin hole leak in one of the hoses off of the thermostat housing. Replaced, bled system and couldn't replicate overheating.
Picked up the car today and same thing after about an hour on the highway temp creeped up about 1 tick above the middle, turned the heat on full blast and went back down. If i turn the heat off the temp will creep up but if I leave the heat on its fine.
The shop ruled out Head gasket as there are no symptoms of head gasket, no smoke, no oil/coolant mixture, and the system pressure tested fine.
I am completely stumped at this point, I initially thought an air bubble was the culprit but I bled the car and the shop bled the car with no signs of an air pocket. The only aspect of the cooling system untouched would be the radiator, but I am not completely sold.
Any insight?
*Not entirely related but my a/c compressor went out (pulley shot) a few months ago and haven't got around to swapping it out yet, but figured I'd note it.*
Make sure system is bled of air. If you are 100% positive the system is bled is your temperature sender/sensor ok?
Yes, I am sure the system is bled of air. There doesn't appear to be any issue with the temp sender/sensor as it is reading the temperature fine. When it says it is starting to get hot it is starting to get hot.
Well when ever I have had an issue with the heater blowing cold after the engine was warmed up or hot it was because of an air pocket. When you bled the system did you have your heater running? I am sure you have checked the radiator but if you haven't you can always try a flush.
But getting back to the sensor, it doesn't only read temp and display it. It tells the ECU what the temp is and the ECU will make adjustments accordingly. It could be causing your engine to overheat. At this point you don't have a lot of options, you've changed everything so what do you have to lose. If it turns out not to be your Temp Sensor then your ECU could be a problem I guess.
Well when ever I have had an issue with the heater blowing cold after the engine was warmed up or hot it was because of an air pocket. When you bled the system did you have your heater running? I am sure you have checked the radiator but if you haven't you can always try a flush.
But getting back to the sensor, it doesn't only read temp and display it. It tells the ECU what the temp is and the ECU will make adjustments accordingly. It could be causing your engine to overheat. At this point you don't have a lot of options, you've changed everything so what do you have to lose. If it turns out not to be your Temp Sensor then your ECU could be a problem I guess.
Yes I had the heater running while bleeding it, and the shop bled it for over half an hour and didn't see any signs of an air pocket. We have pressure tested the radiator and the entire system with no issues being found.
At this point the only thing I can think left is the radiator. I am hoping it has some debris on the front of it which is causing air flow issues, but even that does not seem likely, and I won't have a chance to pull it apart until next week.
I think the coolant temp sensor and/or ecu are extremely unlikely given the symptoms.
If it’s not an air pocket, which I don’t suspect since you’ve bled it, I agree with the radiator. I had a Honda Accord that had over 200k on the original radiator. It didn’t leak but would get hot on long freeway runs in the summer. When I got around to diagnosis, the radiator fins pretty much fell apart as removed it. I’m guessing the was a blockage. You could inspect the radiator but ultimately since you’ve already replaced the water pump and other parts, might as well replace it.
As of 2017-07 I have an 2013 IS-350 which behaves a lot like yours minus the overheating....
That is, compared to previous 3.0 V6 of 2006 it takes roughly 3 to 4" longer to come up to temp. And if idling in traffic the fans are off and on constantly but it never over heats even when ambient hit 100+F. That said, your words about not being under load sometimes I end up jacking the heater to 77F to stay warm while other times 72F is just fine. To your point it is load dependent....
The past weekend it was used hard on a long cruise doing 85/95 mph up a 6% grade for like 14miles and no issues. Same on the flats cruising at 90mph and happy as could be. But, going down those long grades there was no load and the heat had to be turned up. My point is the design and/or function seems to ride right on edge.
FWIW - you know the gauge is normalized so in most conditions the needle remains parked just left of middle marker even though the actual water temp is swinging roughly +/-20°F... They would have people crying if the needle moved with every temp change.
Please connect an OBDII reader and software and tell us the actual temperatures...
Also, has it ever pushed steam into the air from an actual boil over condition??? If not, it is a tell tale sign it is not actually overheating but ECT sensor is in fact failing.
Basically at 175°F the needle parks itself to the left of the middle mark. Here it only hit about 185....
My point is this; your temp sensor could be deffective if your engine is not actually pushing fluid out from a boil over. Has it made a steam cloud from under the hood?
Basically at 175°F the needle parks itself to the left of the middle mark. Here it only hit about 185....
My point is this; your temp sensor could be deffective if your engine is not actually pushing fluid out from a boil over. Has it made a steam cloud from under the hood?
Yes it has actually gotten hot and boiled over. It is not just a faulty sensor showing false readings. That much I can assure you. After talking to several mechanics I am pretty confident at this point it is just a failing radiator. I just ordered one and will throw it in next week and update further.
I've just recently started to get coolant over flow. I replaced the cap about 5 months ago, and drained and filled the coolant. I'm finding coolant splattred all over the front of the engine. This whole time my car has not over heated. So this morning check and there it was again coolant everywhere. It' coming from the reservoir cap. So I had a new thermostat that I bought before. Just to lazy to install. I will monitor it a few more days. Hopefully it is the thermostat. The car needle is actually showing at a lower position than before. The water pump seems fine no leaks anywhere. Worst case I will just buy a new radiator before I change the water pump. Car is at 70K now.
From the last picture the bottom piece on the new thermostat inside the spring was at a lower position. Does it mean it's open? Vs closed position.
Mike, one tiny thing I have seen happen several times is the inner seat on the cap gets debris in it and or the flapper gets crap under it and either can alllow it to push fluid into the reservoir as the temp goes up. That said, debris under either or material build up or a slight defect in the landing inside the radiator where the inner seal contacts the landing and the engine block won't refill upon cool down. This seldom presents as a coolant leak but can overflow the reservoir.
As the block cools it forms a vacuum and the flapper opens allowing coolant to be pulled from the reservoir.
Another strange failure mode is leaks in the hose from the cap to the reservoir. Here it can boil over but it doesn't refill on cool down.
OP, do you have a device to read the actual engine temp from start up to operating temp?
JM2C but be very careful using worm drive clamps on plastic fittings as they distort and compress the plastic when subject to repeated heat cycles. Then they seap so we tighten the clamp. This lead to complete cracking of a plastic housing.
Just saying the OEM clamps offer 360° of clamp force without a flat spot creating non-uniform pressure.
McMastercarr has SS clamps with tensioners that offer 360° clamp force...
JM2C but be very careful using worm drive clamps on plastic fittings as they distort and compress the plastic when subject to repeated heat cycles. Then they seap so we tighten the clamp. This lead to complete cracking of a plastic housing.
Just saying the OEM clamps offer 360° of clamp force without a flat spot creating non-uniform pressure.
McMastercarr has SS clamps with tensioners that offer 360° clamp force...
FSPORT is referrng to these type of clamps. I always keep a few on hand. RockAuto carries them. Just get the diameter close to the stock hose diameter.
Mike, one tiny thing I have seen happen several times is the inner seat on the cap gets debris in it and or the flapper gets crap under it and either can alllow it to push fluid into the reservoir as the temp goes up. That said, debris under either or material build up or a slight defect in the landing inside the radiator where the inner seal contacts the landing and the engine block won't refill upon cool down. This seldom presents as a coolant leak but can overflow the reservoir.
As the block cools it forms a vacuum and the flapper opens allowing coolant to be pulled from the reservoir.
Another strange failure mode is leaks in the hose from the cap to the reservoir. Here it can boil over but it doesn't refill on cool down.
OP, do you have a device to read the actual engine temp from start up to operating temp?
Thanks. I just went for a drive, and pushed it hard so far no fluid boiling over. It seems it's likely happening while driving. Parked and idling seems fine. I'll let it cool down to draw out the overflow again then go for a long drive tonight.
11-13-17, 08:35 PM
Bad Radiator?
