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2004 Dodge Stratus R/T Sedan, 2.7L V6, 145,000 miles
Otherwise in great condition, well maintained.Spent a couple hours in stop and go traffic in 70 degree weather. Temp gauge rose, and the coolant pressure container cap (like radiator cap, except its not on the radiator) popped opened, flowing coolant into overflow tank which in turn blasted coolant all over my passenger side strut tower cuz that’s where the vent hole in the top of the overflow tank points. The A/C wasn’t running. (I pulled the A/C relay last year cuz the compressor starting failing.)
Pulled over, let the car cool, and everything appears fine after several drive cycles.
Coolant level is good. No leaks. The cooling system has been regularly maintained since 35k miles with regular cooling flushes. It’s clean and free of corrosion or build-up. Water pump was replaced last September, has 8k mile on it. (Original water pump was replaced at 111k miles in 2012 cuz it leaked.) Thermostat has never been changed, but it looked clean perfect in 2012 and functioned properly. Fuel trims are normal and the car runs great.
Electric cooling fans come on at 220 degrees like they’re suppose to. I swapped the low speed and high speed cooling fan relays to make sure the high speed relay was working (which would have come on at 230 degrees when the car was overheating – otherwise they usually don’t go high speed).
The car has never overheated before, despite being put through much worse. Why now?
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Replies
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A few possibilities:
Check your coolant mixture
A faulty radiator cap
A faulty thermostat
You built up excessive temperature/pressure with in the system
Most likely due to one or more of the above reasons.1) Mixture is a perfect 50/50 of distilled water and O’Reilly Universal Antifreeze which I’ve been using for years. It’s been drained and refilled enough that there isn’t any original left.
2) Faulty cap how? Cap seal is good. Cap could be weak and opened before 16 psi I guess, but how would this allow the temp to rise? And it hasn’t happened since.
3) I highly doubt the thermostat caused my overheat for the reason described above, plus I’d been driving for hours with a presumably open thermostat. I don’t think it just closed and stuck shut several hours into my drive. ( I was driving from Seattle, WA to Salem, OR.)
4) Well I sure did have an excessive build up of temperature (which means the pressure rose also, which popped the cap). The question is why? Cylinder compression appears to be fine and I have zero symptoms of a head gasket failure, so I can’t imagine a source of any additional pressure. The question is why wasn’t my cooling system removing the temperature as it has done successfully since 2004.
1) Mixture is a perfect 50/50 of distilled water and O’Reilly Universal Antifreeze which I’ve been using for years. It’s been drained and refilled enough that there isn’t any original left.
Just a suggestion2) Faulty cap how? Cap seal is good. Cap could be weak and opened before 16 psi I guess, but how would this allow the temp to rise? And it hasn’t happened since.
The radiator cap seal is only one part of its function, the spring release will determine the pressure the system will attain.3) I highly doubt the thermostat caused my overheat for the reason described above, plus I’d been driving for hours with a presumably open thermostat. I don’t think it just closed and stuck shut several hours into my drive. ( I was driving from Seattle, WA to Salem, OR.)
Possibility that it may have gotten stuck ( momentarily or partially ) in the closed position is still possible ,as likely as on may get stuck in the open position4) Well I sure did have an excessive build up of temperature (which means the pressure rose also, which popped the cap). The question is why? Cylinder compression appears to be fine and I have zero symptoms of a head gasket failure, so I can’t imagine a source of any additional pressure. The question is why wasn’t my cooling system removing the temperature as it has done successfully since 2004.
Engine cooling is still a simple loop system…
If your 1000% sure about the factors listed
Every consider the possibility a partially internal blockage in the radiator, or perhaps the block itself.
Another possibility …debris blockage limiting air flow, clogged cooling fins is not uncommon..
Faulty radiator hose.. collapsing.
Poor circulation due to a failing water pump ( new replacement parts have been known to fail prematurely )Might also check for the possibility for some type of excess load on the engine Via some accessory or from the transmission or brakes
Good suggestions. I’ll double check the following:
-Triple check for leak that would have caused a low coolant situation which would explain all of this.
-Airflow blockage on radiator
-Excess load:
-I’ll jack up each wheel and give it a spin
-The A/C was failing but I’ve removed the relay. I’ll pull the belt off and make sure the pully still spins freely.
-Idk how to check for a problem in the trannyI’m not concerned about internal blockage. The coolant passages on the block were super clean when I last had the lower intake manifold off.
I inspected the integrity of the hoses when I recently did the water pump and im not concerned that they’re collapsing.
What would be the mode of failure of the remanned aftermarket water pump? Could it be intermittently failing to spin? I would assume that the drive gear, the shaft, and the impeller were all assembled to eachother in such a way that that wouldn’t be possible. However, I can see were if the impeller were just pressed on, maybe it could be slipping on the drive shaft. Since the overheat, i’ve developed a consistent sqeaky whistle from one of the pulleys also, maybe the wayer pump? …
On a final note, the car overheated last night. I took several 20 min jaunts on the freeway, and was driving all around town. It hit 230 deg once while idling in the drive thru and the fans quickly brought it back down. (It’s normal to hit 220 which kicks on the low speed fan, but that usually prevents it from going higher.) Anyway, on the final 20 min drive home, the temp hit 248 and my overflow tank filled with coolant.
[i]What would be the mode of failure of the remanned aftermarket water pump? Could it be intermittently failing to spin? I would assume that the drive gear, the shaft, and the impeller were all assembled to eachother in such a way that that wouldn’t be possible. However, I can see were if the impeller were just pressed on, maybe it could be slipping on the drive shaft. Since the overheat, i’ve developed a consistent sqeaky whistle from one of the pulleys also, maybe the wayer pump? …
[/i]I can not say how your water pump was assembled, but I have seen impellers slip in their drive shafts.
As to the “sqeaky whistle”:
Could be the water pump or another drive accessory or tensioner failing or perhaps a slipping fan belt.On a final note, the car overheated last night. I took several 20 min jaunts on the freeway, and was driving all around town. It hit 230 deg once while idling in the drive thru and the fans quickly brought it back down. (It’s normal to hit 220 which kicks on the low speed fan, but that usually prevents it from going higher.) Anyway, on the final 20 min drive home, the temp hit 248 and my overflow tank filled with coolant.
From this description and the fact your vehicle is equipped with electric cooling fans…
I would bet that your looking at a partial blockage inside the radiator which will limit the cooling capacity the radiator will provide.
If that is the case, I can understand the fans both having to work longer in an attempt to cool the radiator at idle, while driving there is greater air flow across the radiator.I had a similar issue a few years back, when the outside temps were below 80*F car ran fine.
Over 80 – 85*F it would start to get hot at idle, but if you were rolling, temps would drop back to normal.FYI, I had done a system flush, replaced the water pump, fan clutch, thermostat, hoses.
Even went as far as check the flow through of the radiator, appeared the water would flow out as fast as it went in.
But the cure came, after replacing pretty much every thing, installing a new radiator solved the problem.
Did it bother me having replaced all that hardware…. actually no, it was 10 years old and I’m sure was getting close to the end of its serviceable life.I didnt read all of night’s suggestions, but maybe as simple as your radiator cap can be replaced. Look at your manual or just buy a cap thats 180psi or something (i’m probably wrong here). That is really strange tho… Your res tank’s cap popped off due to pressure and you know have a cat’s best lickable sugaryisqe liquid everywhere? Keep us updated if you’re telling the entire truth.
[quote=”creativepotato” post=167163]… if you’re telling the entire truth.[/quote]
Huh?
Anyway, to clarify further: I doubt I have a radiator blockage. If I do it will be unfortunate, cuz I’m so skeptical that I’ll probably get rid of the car before I throw money at a new radiator.
And it isn’t getting hotter at idle. The last time it overheated, was on the freeway at night.
And the radiator cap (actually “coolant pressure tank” cap or whatever, didn’t “pop off.” It popped open like it’s suppose to do in order to let coolant flow into the overflow tank. But because the overflow tank filled almost 100%, coolant came out the vent in the top of the overflow tank and covered my strut mount area. There’s no coolant on driveway. The cats are fine.
[quote=”nightflyr” post=167124]I can not say how your water pump was assembled, but I have seen impellers slip in their drive shafts.
[/quote]This is very interesting. I should try to narrow down the source of my squeak. It’s a consistent squeak. It’s either the power steering pump, the A/C compressor, the alternator, or the idler. But it didn’t start until after the first overheat. And the only pulley that really got some coolant splashed on it was the crank pulley/harmonic balancer which surely isn’t squeaking. But I doubt it’s the water pump squeaking because the squeak is so consistent that I would find it hard to believe the impeller is slipping all the time and still spinning enough to keep my cool most of the time until it hypothetically starts slipping so much that it’s no longer spinning at all.
Unfortunately, it’s a LOT of work to take the water pump off and have a look.
Verify that the coolant system can hold at least 16 psi., Maybe but some trace dye in and pump it up to 18psi let it set will you check for leaks. Also check that the cap is holding at rated pressure.
At 16psi coolant can reach 270F before boiling but at 8 psi will boil at 250F
Ok, I’ll rent the pressure testing thing from the auto parts store that should let me also test the cap.
Update, though: I took a whiff of the inside of my coolant pressure container and it smells to me like exhaust gas. So I’m gonna have to figure out how to check the coolant for combustion gas contamination. And I’ll do a compression check also.
Sounds like a plan.
If head gasket is breached from coolant passage to combustion chamber that may show up in a pressure test of the coolant system.
Regarding combustion gas test, auto parts store should have chemical test kit to loan.If you see no evidence of white smoke from the tail pipe, pressure testing the cooling system in hopes of finding a combustion gas leak into the cooling system may not yield the proper results.
If you suspect a breach..
Combustion leak test the system.
If positive then:
Perform a leak down test on each cylinder with the radiator full and cap removed.
Then you will be able to isolate which cylinder(s) are affected.I would say pressure test the cap to make certain that it is holding the proper pressure. As a previous poster pointed out, at lower pressures, the coolant will boil at lower temperatures, so if the cap is releasing early, say at 8 or 10 psi instead of 18, you could be boiling over before the cooling fans can pull the temperature down.
Cooling system pressure test was inconclusive. I believe the rental tool actually leaked pressure.
Combustion gas leak test AKA “block test” revealed a combustion gas leak in the cooling system. This was the test where I draw air from the cooling system up into a cylinder full of reactive liquid that changes color when exposed to combustion gases.
So it appears that as the car warms up a small leak from one of the cylinders is pressurizing my cooling system. This causes the radiator cap to vent coolant to the overflow tank. Once I lose enuf coolant to the overflow tank, the car becomes more susceptible to overheating from all the air in the cooling system. I’m going to start a new thread to explore causes for the combustion gas leak. Cracked block, cracked or warped head, gasket issue?
Here’s the link to my new thread. Please reply there.
https://www.ericthecarguy.com/kunena/8-Service-and-Repair-Questions-Answered-Here/65172-cause-of-combustion-gas-leak
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