B serious

***UPDATE***

This turned out to be a blown head gasket

https://www.s2ki.com/forums/s2000-under-hood-22/so-ive-blown-my-head-gasket-1207957/#post24845568

I have a MY2007.

It has 168K miles.

It has a Koyorad. The filler neck is dented, but the cap doesn't leak externally.

PO had the car supercharged. But I've owned it over 2yrs now.

I was tracking the car at Autobahn CC this past summer/fall.

When I pulled into the paddock, I noted that I had a lot of coolant splatter all over the engine bay from my overflow tank and the overflow tank was MASSIVELY full.

I drained 2 water bottles worth of coolant out of it to bring it down to the "max" line. That's like 32oz.

The car never overheated and I had no clue what the deal was. No milky oil. No gray coolant.

I continued tracking it and driving it since then. The coolant level NEVER changed after that.
Also very strange. Its like the car just "made" 32oz. of coolant.

I left town for a while. Car was parked for 1 or 2 months.

I get back to town and now the weather is a bitterly cold, barely survivable 55F.

I drove my AP2 to go buy a woolen shirt to help deal with this.

I tried to crank the heat and its blowing cold! I'm like a delicate flower. I'll perish under these conditions.

I guess I got massive air in the system?

Idk how. But obviously the overflow and no heat incidents are related.

Come to think of it, I saw coolant spatter from the overflow at a few other track events also.

Idk what is going on.

I'm starting this thread for any tips y'all may have. Additionally, I'll post what I try and what solutions I find.

Billman250

At no point do you mention checking the level in the radiator. Was it ever low?

B serious

well...I feel like a dumby.

I didn't check it in the past because I didn't even realise the heat wasn't working. But..I should have because 32oz of coolant came out.

Its low.




But...what caused the coolant to surge up like that in the first place?? The car never overheated....

Maybe a bad rad cap allowing too much bypass?

B serious

This is becoming less of a mystery. Idk why I was so perplexed.

The most logical thing is a bad radiator cap allowing too much bypass.

I'll try a new cap and coolant refill/bleed.

:facepalm:

nate.the.great

Sometimes it's hard to see what's right in front of us. I can just imagine you re-reading the above quote...

B serious

Actually, most of my regret comes from telling everyone this

windhund116

The experience of Billman, to the rescue once again!

Billman250

I feel the radiator cap fit may be off, preventing drawback of the coolant from the resovior. An all oem radiator setup stays full always. You got the coolant a little hot and sent it into the res, but the rad didn’t draw it back.

Top cap seal is responsible for drawback.

The car needs to be tested to see if it’s drawing coolant back into the rad.

I have always thought the caps on the alum rads have poor fitment.

afzan

your symptoms remind me of similar issues I had on a beater, it ended up being a bad rad cap

B serious

Yep. The reservoir level stayed the same this whole time. So I took for granted that the radiator wasn't low. I was wrong

Idk if this issue has something to do with the slightly dented water neck (looks like someone dropped the radiator on the water neck...with the cap on).

If the new cap doesn't work, I'll have to buy a radiator.


New cap is en-route!