I just noticed two weeks ago that my dash temp gauge needle was not at its normal spot while at a stop light(sitting just a hair below the wavy lines near the middle of the gauge). It was between the H and the tickmark below it. I have a Cobb AccessPort and always monitor the coolant temp, will explain why below, so when I looked at that, the temp was at 200 degrees. In the past 205 degrees would still keep the dash gauge rock steady the middle and the fans would kick on at 207 degrees. After moving again the dash gauge came back down to the normal range and the Cobb App was showing around 190 degrees. Anything close to 192 and up would cause the dash gauge to move now.
I have an 06 STI stage 2 Cobb w/mishimoto radiator and stock radiator caps. I rebuilt the engine with a new OEM short block at 215,000 miles. I had headlift/head gasket issues and I was pushing coolant into the overflow tank. I struggled with this for over a month testing and trying all sorts of things hoping it wasn't the heads. So I am familiar with all of the problems that go with head gasket issues as i had to burp my coolant system every day in order to drive the car. Because of this I have always monitored my engine temps. 205 was always the normal hot temp with the fans kicking in at 207.
Now at 3 years later at 230,500 I'm going through my checklist again.
I let the temps come up and around 191 degrees the dash gauge started to rise. I then realizes that the amount of coolant in the Lisle funnel was increasing a little around 195 degrees. Then at 200 degrees the funnel was now up to half filled. Worried it might over flow I plugged the funnel and I turned the AC on to help cool the radiator. At this point i could see the top radiator hose suck in a bit so i pulled the plug and the car sucked almost all of the coolant back in. So i could then repeat this process. As the engine temps go closer to 200 the funnel would fill, I could then turn the AC on and the fans would bring the temp down and the coolant level in the funnel.
Yes, Yes i know coolant expands when hot but i have burped the coolant system dozens of times up to 207 degrees where the fans kick in and never seen coolant push into the funnel like this. So here lies my confusion. Originally i thought it was a bad dash gauge since the Acessport never showed temp changes that matched the dash. But after seeing the coolant expand and fill the funnel could the water pump be the issue. Could it not be circulating the coolant and the path of least resistance for the expansion was up into the funnel.
Before I jump into a water pump replacement I'm just looking for any other thoughts on what could be causing this. Engine temps have been fine for 3 years and nothing has been done to the engine other then oil changes in this time.
I have an 06 STI stage 2 Cobb w/mishimoto radiator and stock radiator caps. I rebuilt the engine with a new OEM short block at 215,000 miles. I had headlift/head gasket issues and I was pushing coolant into the overflow tank. I struggled with this for over a month testing and trying all sorts of things hoping it wasn't the heads. So I am familiar with all of the problems that go with head gasket issues as i had to burp my coolant system every day in order to drive the car. Because of this I have always monitored my engine temps. 205 was always the normal hot temp with the fans kicking in at 207.
Now at 3 years later at 230,500 I'm going through my checklist again.
- I'm not low on coolant.
- I'm not pushing any coolant into the overflow tank/ no bubble or material in the coolant.
- My radiator fans still kick on at 207 degrees.
- Cobb AccessPort has never shown the temps going above 207 even though the dash gauge displays like it is.
- I burped the coolant system 2 times.
- I replaced the thermostat and coolant with OEM.
I let the temps come up and around 191 degrees the dash gauge started to rise. I then realizes that the amount of coolant in the Lisle funnel was increasing a little around 195 degrees. Then at 200 degrees the funnel was now up to half filled. Worried it might over flow I plugged the funnel and I turned the AC on to help cool the radiator. At this point i could see the top radiator hose suck in a bit so i pulled the plug and the car sucked almost all of the coolant back in. So i could then repeat this process. As the engine temps go closer to 200 the funnel would fill, I could then turn the AC on and the fans would bring the temp down and the coolant level in the funnel.
Yes, Yes i know coolant expands when hot but i have burped the coolant system dozens of times up to 207 degrees where the fans kick in and never seen coolant push into the funnel like this. So here lies my confusion. Originally i thought it was a bad dash gauge since the Acessport never showed temp changes that matched the dash. But after seeing the coolant expand and fill the funnel could the water pump be the issue. Could it not be circulating the coolant and the path of least resistance for the expansion was up into the funnel.
Before I jump into a water pump replacement I'm just looking for any other thoughts on what could be causing this. Engine temps have been fine for 3 years and nothing has been done to the engine other then oil changes in this time.
