Blew a hose, coolant everywhere, now having heating issues
 

I dont post a whole lot on here, so some quick details.

MAPerformance turbo kit
Fullblown stage 1 shortblock
Delicious FlexFuel tune
450whp on E85 (roughly)

So I went out the other night to datalog a 3rd gear pull for Zach, like I have done many times in the past. But this time, right as I got to redline I got this huge wiff of coolant coming from the vents, and a bunch of white smoke coming out the tailpipes (but only for about 5 seconds or so).

Made it to a gas station about a 1/2 mile up the road. Popped the hood. Coolant was everywhere. The entire engine covered.

The little hose that goes from the radiator cap to the overflow tank blew off.
Thats all I could see. I was eventually able to get about 2 quarts of coolant in before leaving the gas station. No other leaks anywhere that I could see.

Temp held steady at 190-191F the rest the way home, but I had the heater on the whole time.

Drove it to work the next day, and the temp kept fluctuating. It would get up to 203F and then drop fairly quickly back down to about 190F, stay there for a bit, then back up it would go again.

Thought there might be some air still in the system, so I took the radiator cap off and started up the car. Now until the thermostat opened up, I would occasionally see little bubbles. But also, the coolant would slowly rise and start spilling over the edge (is that normal?)

After I let it idle for about 20-30mins I was barely able to get any more coolant in. Drove it home with still the same up and down fluctuation.

While it was parked in the garage I held the throttle at about 2.5k rpms with heater off, and the temp started rising again, but when I turned the heater on full blast it started dropping back down.

The car has always held a very consistant 194F up until this point.

I cant see any smoke coming from the tailpipes, though on startup it smokes briefly. Pulled out the dipstick and the oil didnt seem milky.

Originally thought headgasket, but not seeing any symptoms.

Thoughts?

Faulty thermostat?
Has all the classic symptoms.

If that is the case, its things like that, that just baffle me.

The thermostat has been operating just fine, and after a little hose blows off, its now faulty?

That does seem most likely though... To put my whole story simply, the coolant temp fluctuates between 190F and 203F. It rarely stays at a constant temp, unless I blast the heat.

No harm in replacing it. Im assuming you can have it tested though first? Or just screw it and replace it?

You are mixing up cause and effect. The hose blew off because the coolant got too hot not the other way around.
Cheap and easy enough to just replace it and see if that is it.

all hail tcoat. :cheers:

Did you follow the proper bleeding procedure given below, or did you just fill up the radiator and let the car idle?

http://www.ft86club.com/forums/showthread.php?t=9883

All I did was fill it up and let the car idle... Then turned it off and let sit for a bit, then checked the level again and kept repeating.

I knew there had to be a bleeder somewhere. Ill try that first before replacing the thermostat.

One thing I noticed when I had the car in the garage revving it, is when I turned on the heater and swore I was hearing some weird noise that I dont ever remember hearing. He says in step 20 that if you hear a flowing sound to repeat previous steps.

Im hoping thats all it is... Thanks!

Something caused it to blow in the first place. Bleeding it is just treating the symptom not the root cause. Change the thermostat and then bleed.


Due to your mods it may even be a good idea to go with one that opens at a lower temperature. It may not be your issue but it has all the symptoms. No sense risking your whole build for the sake of a $30 thermostat.

Yes master :bow:

I know you're the King around these here parts :) . Ill look into getting one that opens earlier.

When do ours open? Im pretty sure my gauge was reading well over 180F before I noticed it open.

Nobody's "master" and certainly not "king" just trying to help.

It is supposed to open at 95 degrees. The performance ones open between about 75 and 80.


The big give away to me is that putting the heater on helped maintain the temp since it was working as the rad while the coolant was not flowing properly.


I could be wrong and it may have nothing to do with your issue but I have toasted an engine before due to a bad thermostat and every single thing you stated is exactly what happened to me. Need to find and fix the cause with these things not just treat the results.

Ill try and refrain from using those words in the future... 95C is 203F, and thats the exact temp it would hit before dropping back down.

So we know its opening, and it must close in order for it to rise again correct?

I suppose we could talk about this all day long... Ill just have to replace it and see what happens.

Totally up to you of course but that is where I would start if I had the issue.

Fully agree with the advice in this thread thus far.

High quality thermostat. (Read: OEM, Cosworth, if there's a TRD/STi part available, that's good.) NOT Mishimoto!

OEM coolant, high quality tstat, silicone hoses if you want em, and a proper bleed.

You shouldn't need to go with a lower temperature, I honestly see that as Tcoat so eloquently said, that's treating a symptom not the cause. The cause is the potentially underwhelming cooling solution for this car when boosted. These cars like to have an oil cooler, and if you have FI, it becomes a requirement IMO. With FI, the radiator gets worked a lot, so adding a part like the Koyorad is a great idea.

Edit: If I owned a boosted 86 I'd consider the Jackson Racing dual radiator system that integrates an oil cooler into an oversized radiator.

I have never had any cooling issues of any kind until this happened. My oil temp has never gone above 230F, and thats with no oil cooler, and I have never seen my coolant temp go above 197F. The whole cooling system is stock.

Thats why Im hoping its something simple, like an improper bleed, or in this case, no bleed at all, or a faulty thermostat. Unless something else happened right at the moment the hose blew off. :iono: