Overheating/Leaking (spewing) coolant from cap

Usmcpi

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So about a week ago, my car started overheating. Noticed the reservoir was low, added water. Still overheated and low coolant. What it does is get to the normal operating temp, stays there a few minutes, then proceeds to climb up to 250+ degrees. I saw the coolant was spewing from around the pressure cap and I thought maybe around the reservoir seam, so I replaced both the cap and the reservoir. Same issue. What causes this excessive pressure to blow out all my coolant from the overflow cap?

It may be important to note:
a) This originally happened the say I took my car through an automatic wash, which I rarely ever do. I don't have the engine underbelly plastic on. It's probably just a coincidence, but thought I'd mention it.

b) I thought I had a head gasket leak over a year ago and put some KW fiberlock seal in, it's been in there ever since. Turns out I didn't have a head gasket leak before and it was just the check valve thing on the upper rad hose leaking. Replaced the hose and no more problem.

2010 SHO w/ 108k miles
 

luigisho

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How does the oil look? any coolant leak outside the vehicle? The internally mounted waterpump can leak internally. Excessive pressure might just be thermal expansion of the coolant and gasses in there. Check the oil for coolant, check the ground for coolant, run a code scanner on the computer see what's what.

Here is a waterpump failed 3.5
 

Usmcpi

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oil seems fine, a bit dirty as I'm due for a change, but its a solid dark brown. The only place I can really see it leaking from is the reservoir area, just pouring straight down. The last time I drove it, it did go into a limp mode, now I have the following codes:
P0299 Turbo A underboost
P0430 Catalytic efficiency below threshold bank 2
P1285 Cylinder head overheating
P1299 Cyl head overheating protection active
P1000 OBD readiness incomplete (due to tune)
P1602 Immobilizer/ECM communication error (this one always comes and goes)
 

luigisho

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I wonder if that fiberlock gummed up the radiator or other passage? I really hate those additives. Have some worked for some people before? yes. I know alot of people where it did not work and wound up just making a mess internally.

I also wonder if there is wiring that can get affected from the underwash. Have to see the sensor wiring and check those. HAve you noticed vehicle performance changes? The 1st code is underperfoming turbo charger. I am ok with naturally aspirated cars but people more familiar with turbo issues will have to chime in on this. Usually the most pertinent diagnostic codes pop up first
 

Usmcpi

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I'm pretty sure all the codes (besides the p1000 and p1602) are just from the limp mode/over heating on the most recent drive. I cleared them, but I guess I'll see if they come back when I take it for a quick drive later.
 

luigisho

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I'm pretty sure all the codes (besides the p1000 and p1602) are just from the limp mode/over heating on the most recent drive. I cleared them, but I guess I'll see if they come back when I take it for a quick drive later.
Good idea. Watch the temps. You don't want a paperweight under the hood
 

Substantia Nigra

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Is there white smoke coming out of your exhaust? If not, and your oil truly isnt chocolate milk, it's leaking outside instead of internally. Maybe the coolant reservoir cap pressure valve is bad.
 

rubydist

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Bad thermostat and bad cap are the two most likely problems. After it got hot the first time, the thermostat is most likely sticking so I would replace that anyway.
 

Bluezone

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oil seems fine, a bit dirty as I'm due for a change, but its a solid dark brown. The only place I can really see it leaking from is the reservoir area, just pouring straight down. The last time I drove it, it did go into a limp mode, now I have the following codes:
P0299 Turbo A underboost
P0430 Catalytic efficiency below threshold bank 2
P1285 Cylinder head overheating
P1299 Cyl head overheating protection active
P1000 OBD readiness incomplete (due to tune)
P1602 Immobilizer/ECM communication error (this one always comes and goes)
From the sounds of it you got an air bubble in the system at the very least. If you're having trouble getting rid of it air bubble. Take the pressure cap off and fill the coolant bottle to at least the hot fill level. Then idle the engine until it reaches operating temperature. Then run the engine at 3000 RPM for a minute. Let it idle for 30 seconds and shut it off.
Allow the engine to cool for 20 minutes to a half an hour. Rinse and repeat twice more. If there is air in the system this should remove it. If possible have the passenger side front of the car lifted to make an easier path for the air.
I agree that replacing the thermostat before doing all this might be a good idea.
Also make sure that your cooling fans are coming on. From the sound of it, the fan is not likely the problem.
When you're starting to get communication errors between different modules, it might be a good idea to check the battery voltage and ensure that the battery connections are clean.
I cleaned every module connector I could lay my hands on. This cleared out communication errors that I was having. Yes the battery post connections as well.
 

Usmcpi

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Is there white smoke coming out of your exhaust? If not, and your oil truly isnt chocolate milk, it's leaking outside instead of internally. Maybe the coolant reservoir cap pressure valve is bad.

No Smoke. I've had the original cap, a new one from auto zone, and the cap that came on the new reservoir - all 3 produce the same result.

Bad thermostat and bad cap are the two most likely problems. After it got hot the first time, the thermostat is most likely sticking so I would replace that anyway.

I'll prolly pick one up from the auto parts store. My only issue is that I need a 160/170* tstat. The auto parts store only shows a 180 OEM temp compatible with the car. How do I know which 160/70 will fit?
 

Substantia Nigra

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You replaced the reservoir with a brand new oem one?

RAT or reische makes the 170 deg thermostats
 

Usmcpi

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Well a knockoff OEM reservoir from Amazon, but yes.

I understand I can look up a 170 tstat from a performance store, but I'm trying to get one today and the online performance part numbers don't dross reference with parts stores like Advance and Autozone.
 

SeanDev

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You replaced the reservoir with a brand new oem one?

RAT or reische makes the 170 deg thermostats
[/QUOTE
Reische is the way to go. Great quality, zero issues and in my opinion puts any brick and mortar stores thermostat upgrade to shame. Being that too, it's been proven, brick and mortar thermostats other than OEM can be 10-20 degrees off. The Reische I've had for a year and half, and is spot on when it needs to open and close.
 
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Usmcpi

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So good news - the tstat was the problem. The one I pulled out was stamped Motorad, and even though the one I bought for $9 at Autozone came in a box that said Murray, the tstat itself is stamped Motorad. So I guess stay away from that brand. However, the one I bought was a 180* unit just for troubleshooting purposes.

So you guys are recommending a 170*, my tune is through LMS which suggest a 160* tstat. Is there a consensus on which is better?
 

luigisho

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Once you swap this clear the codes, run the car, and see what pops up. It might be showing another potential issue if that turbo code is not related to heat
 

Ta2dResqr

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So good news - the tstat was the problem. The one I pulled out was stamped Motorad, and even though the one I bought for $9 at Autozone came in a box that said Murray, the tstat itself is stamped Motorad. So I guess stay away from that brand. However, the one I bought was a 180* unit just for troubleshooting purposes.

So you guys are recommending a 170*, my tune is through LMS which suggest a 160* tstat. Is there a consensus on which is better?
The priority first is the one that your tuner has set the tune up for. They will/can adjust the fan off and on times and that needs to be matched to your thermostat. If they recommend a 160*, I would go with that. Above all, I would recommend a 170* and a new tuner.
 

Usmcpi

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Once you swap this clear the codes, run the car, and see what pops up. It might be showing another potential issue if that turbo code is not related to heat

Oh, it definitely was related to overheating. I cleared them, car ran fine until it overheated and went into protection mode again with the same codes coming up. These codes/protection limp mode have never happened prior to over heating.

The priority first is the one that your tuner has set the tune up for. They will/can adjust the fan off and on times and that needs to be matched to your thermostat. If they recommend a 160*, I would go with that. Above all, I would recommend a 170* and a new tuner.

Yeah, I've heard about the LMS issues. The car came with the LMS tune and I personally haven't experienced any apparent issues. My only concern is possibly leaving gains on the table. Guess we will find out whenever I can finally make it to the strip once it cools down a bit outside.

The only reische 160 I could find is this: https://www.pbdyno.com/Reische-FORD-50-Thermostat_p_261.html
That should fit, right? Is there any concern running a 160 tstat when you have cold winters (Chicago area)? I'm sure I could have LMS adjust tune parameters to suit a 170 tstat.
 
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SM105K

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LOL LMS recommends and tunes with a 160* T-Stat.....******* retards.
 

Majestic

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Stock thermostat will be fine. I'm tuned with LMS and have the stock thermostat with no issues.
 
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