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Phantom overheat
- Thread starter bngl3rt
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- 25 February 2012
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No maintenance records, just a PPI. This was reflected in the price. I am still in for less than I could/would/should have paid for the car if the maintenance history was complete - if we count my time in dealing with this and the years taken off my life by the stress as being worth $0 :wink:
All work since my ownership has been done at Prime-approved shops.
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Empirically, after driving, both radiator hoses are hot to the touch. I will have to measure the difference, if any, between them.
All the hoses were replaced recently, but I understand this only means the rubber bits in the engine bay and under the hood - the hoses in the tunnel are aluminum, right? Could anything have moved/bent them?
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Thanks, ordered.
Both hoses should be hot, but the one coming from the engine to the radiator should be the hotter one and there should be a good deal of difference in temperature between the two or the radiator/fan are not doing their jobs. If I remember correctly the thermostat is set to open at 180F but I could be off a couple of degrees.
You are correct, only the rubber gets replaced.
Another thought is maybe you still have a bubble in there that hasn't been bled out and that could cause some issues to.
Another thought is maybe you still have a bubble in there that hasn't been bled out and that could cause some issues to.
Incorrect there are at least 3 rubber hoses in the "tunnel" covered by a plastic cover underneath the car that need to be replaced as well.
Yup 3 rubber hoses & pipes. Radiator inlet, radiator outlet, and the split-off to the heater core.
If you can turn the heater on and it blows hot immediately, and the water temp gauge doesn't drop significantly, then it's unlikely you have a bubble.
If both radiator hoses are hot to the touch, then I suspect you'll be able to confirm no flow restriction with an actual measurement.
I agree that if one of the pipes (generally not a wear item) or one of the hoses were to be in direct contact with the tunnel, that could definitely lead to excess conductive transfer of heat into the cabin.
If you can turn the heater on and it blows hot immediately, and the water temp gauge doesn't drop significantly, then it's unlikely you have a bubble.
If both radiator hoses are hot to the touch, then I suspect you'll be able to confirm no flow restriction with an actual measurement.
I agree that if one of the pipes (generally not a wear item) or one of the hoses were to be in direct contact with the tunnel, that could definitely lead to excess conductive transfer of heat into the cabin.
I don't think a leak in the tunnel would cause any increase in temperature unless it was a stream spraying directly on the underside of the tunnel...and then you'd be a lot more than 1" short.
Also, Coolant does expand and contract as it heats and cools. If you were driving the car regularly and looking at the "hot" coolant level, and then left it sit and are now looking at a cold level, the level reading on the bottle will be different.
I actually calculated the volumetric expansion at one point trying to diagnose my car (needed to know how much room to leave in the expansion tank such that it shouldn't overflow). The level in the bottle definitely varies significantly from hot to cold.
The best way to know would be to pressurize the system with a pressure tester, leave it for a few hours and see if there's a pressure drop. Otherwise, you could get the car on stands/a lift and pull the under-cover to look for signs of dried coolant.
Also, Coolant does expand and contract as it heats and cools. If you were driving the car regularly and looking at the "hot" coolant level, and then left it sit and are now looking at a cold level, the level reading on the bottle will be different.
I actually calculated the volumetric expansion at one point trying to diagnose my car (needed to know how much room to leave in the expansion tank such that it shouldn't overflow). The level in the bottle definitely varies significantly from hot to cold.
The best way to know would be to pressurize the system with a pressure tester, leave it for a few hours and see if there's a pressure drop. Otherwise, you could get the car on stands/a lift and pull the under-cover to look for signs of dried coolant.
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Nope. I only did this because I had fixed some leaks and after re-filling and bleeding the system, I was trying to determine if I was over-filling an aftermarket coolant tank, or if the car was pushing coolant under load (unfortunately it was the latter).
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So it turns out to have less to do with "hard" driving vs ordinary driving, and more to do with whether I have the heat/AC on. If I turn the CCU OFF, I feel the shift boot starting to heat up. If I turn it on (doesn't matter whether I have heat or cold selected, though post-having the engine out, cold only works for outside air, inside air is warm), the heat in the shift boot goes away.
It just happens that when I am driving "hard" I turn the air off because I want to hear the engine, not the blower :smile:
So, this suggests to me that turning on the air, regardless of what temperature you are set to, affects the path of the coolant (right?) and the path that the coolant takes when the CCU is OFF is bad/inefficient/blocked/in contact with the tunnel/something else.
I had a long drive along a boring highway today during which I could experiment. I drove the last bit with the CCU off and noticed a fair bit of heat radiating from under the car onto my foot when I got out as well.
It just happens that when I am driving "hard" I turn the air off because I want to hear the engine, not the blower :smile:
So, this suggests to me that turning on the air, regardless of what temperature you are set to, affects the path of the coolant (right?) and the path that the coolant takes when the CCU is OFF is bad/inefficient/blocked/in contact with the tunnel/something else.
I had a long drive along a boring highway today during which I could experiment. I drove the last bit with the CCU off and noticed a fair bit of heat radiating from under the car onto my foot when I got out as well.
Ditto this as my first thought. I had to bleed a prior mid engine car about six times once to get all the air out. These mid engine cars can be very difficult to bleed and even a master mechanic can easily be fooled. Make them bleed again with the rear raised. i bought a coolant system bleeding kit from snap on for the next time i do mine. Changing the coolant in this car makes me nervous and i'm not unexperienced.
Get the IR gun. Ideally you could get together with another x'r and take temp readings after a drive at various loc's perhaps yielding a clue.
Certainly get yourself a pressure tester. If the pressure holds, it's extremely unlikely you have a leak.
Check the CO level again!
Make sure your rad fan is running. Don't worry about the engine comp fan.
While i'm not a SC guy, could there be something that the previous owner did that did not get changed back making the car on the verge even before your head issue. Take your time. While i can't tell you a good place(i'm sure someone can) i would definately add a temporary temp gauge from jegs to make sure you don't do another HG. Good luck!
Yeah, given that the condition changes with the state of the CCU, it's possible there's a bubble in the heater loop. There's a very particular ritual to bleeding the coolant system (unless you're using a vacuum/venturi bleeder) to make sure all of the bubbles are out of everywhere.
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Rad fan is definitely running when it is supposed to. It was doing so before the HG blew as well, so there is/was some other cause of overheating...
I am checking the oil and coolant levels before every drive now but they seem stable. I think the smell is a pre-existing exhaust leak in my headers which was worsened by uninstalling and reinstalling them.
So turning the CCU on changes the path of the coolant regardless of whether you select cold or hot?
Tangentially, my a/c no longer works after the HG job. I heard it is very easily to accidentally vent the freon while the engine is out. So it really doesn't matter whether I select cold or hot... cold is "hot" and hot is "really hot"
Ok, here's what we're looking at:
Note the small pipe conjoined to large pipe #21, that's going TO the heater if I recall correctly. Then note the small pipe stub sticking up from pipe #20, that's where the coolant returns to the main loop from the heater core. (unless I have the flow backwards, in which case, just reverse the direction).
So it does open up a different path for it to flow. the heater core acts as a small radiator, transferring heat from the coolant to air being blow through the fins of the core, and this of course also reduces the temperature of the coolant as it passes through.
So, it actually does make sense than blower on = cooler tunnel because it's taking heat out of the coolant as it passed through the heater core.
Note the small pipe conjoined to large pipe #21, that's going TO the heater if I recall correctly. Then note the small pipe stub sticking up from pipe #20, that's where the coolant returns to the main loop from the heater core. (unless I have the flow backwards, in which case, just reverse the direction).
So it does open up a different path for it to flow. the heater core acts as a small radiator, transferring heat from the coolant to air being blow through the fins of the core, and this of course also reduces the temperature of the coolant as it passes through.
So, it actually does make sense than blower on = cooler tunnel because it's taking heat out of the coolant as it passed through the heater core.
Two things.
1) Still think it's a bubble. Raise the back of the car by parking on an incline. Start the car and while the CCU is running, bleed all the valves in proper order. This is easy and doesn't cost any money. Your bubble could be in the heater core loop of the CCU and is trapped there. That could cause a pressure build up and steam is way hotter, hence your very hot tunnel.
2) As to the A/C not blowing cold, check to see if they connected all of the compressor lines and wires after they re-installed your motor after the HG replacement. Ask me how I know.....
1) Still think it's a bubble. Raise the back of the car by parking on an incline. Start the car and while the CCU is running, bleed all the valves in proper order. This is easy and doesn't cost any money. Your bubble could be in the heater core loop of the CCU and is trapped there. That could cause a pressure build up and steam is way hotter, hence your very hot tunnel.
2) As to the A/C not blowing cold, check to see if they connected all of the compressor lines and wires after they re-installed your motor after the HG replacement. Ask me how I know.....
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Ok, here's what we're looking at:
Note the small pipe conjoined to large pipe #21, that's going TO the heater if I recall correctly. Then note the small pipe stub sticking up from pipe #20, that's where the coolant returns to the main loop from the heater core. (unless I have the flow backwards, in which case, just reverse the direction).
So it does open up a different path for it to flow. the heater core acts as a small radiator, transferring heat from the coolant to air being blow through the fins of the core, and this of course also reduces the temperature of the coolant as it passes through.
So, it actually does make sense than blower on = cooler tunnel because it's taking heat out of the coolant as it passed through the heater core.
Aha! Thanks for the diagram and the write up. I really appreciate your help and advice in this thread :smile:
Unfortunately I don't have anywhere I can easily put the car up, but I might be able to take it to a friend's place this weekend where I can bleed it and check the compressor lines while I'm at it.
Sounds like we have been through the same wringer with this car... my eyes are glued to my EPS light, lol. At least you are getting 500hp for your troubles, I am bone stock!
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I definitely have a leak. The coolant level is dropping, very slowly, maybe half an inch a day.
When I park overnight I see spots of liquid with stuff stuck in them (coolant is sticky, right?) under the passenger side of the tunnel.
Hoses were recently replaced so what could it be? Pipes? heater core?
When I park overnight I see spots of liquid with stuff stuck in them (coolant is sticky, right?) under the passenger side of the tunnel.
Hoses were recently replaced so what could it be? Pipes? heater core?
Hoses not completely engaged on the pipes? I had that happen when i first had those three replaced at a local place. They only had about ~1/2" of engagement over the pipe on one end....that's not enough.
It would be highly irregular for the pipes themselves to leak unless they've been abused somehow
If it's up in front of the passenger footwell (just rearward of the steering rack), that's where the drain comes out for the AC/Heater, and so could be a heater core. Usually if that's the case though you'll get a strong coolant smell in the car and the passenger carpet might also end up wet if it's a big enough leak.
You/your mechanic need to spend some quality time with a pressure tester to see what's coming out of where.
It would be highly irregular for the pipes themselves to leak unless they've been abused somehow
If it's up in front of the passenger footwell (just rearward of the steering rack), that's where the drain comes out for the AC/Heater, and so could be a heater core. Usually if that's the case though you'll get a strong coolant smell in the car and the passenger carpet might also end up wet if it's a big enough leak.
You/your mechanic need to spend some quality time with a pressure tester to see what's coming out of where.
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Ah, I wish I could find a single mechanic that I could feel good about giving repeat business. Everyone who has fixed one problem with the car seems to have caused another (otherwise the timing of all this is very suspicious). Wish there was somebody that was thorough and not rushed.
I will put the car up this weekend and take a look inside the tunnel to see what's up. It's not coming from the footwell but rather I see a long thin line of coolant that leaked right along the passenger side of the tunnel all the way along it.
