SSK

Howdy, experienced a problem recently and would appreciate any input. Sorry for the long discourse below.

I have a '00 which hasn't really been driven very hard. I drove it daily for about a year; then 6 months ago retired to a garage queen with the addition of a 3rd car. In its service as a daily driver, I never had any problems, the coolant temp gauge was always around 3 bars.

A few weekends ago, I took it up for some... shall we say... "spirited" driving , after 2 hrs of relaxed freeway driving to get there. Ambient temp was around 95-100 degrees here in SoCal. During pre-tech, checked all fluids; I don't recall exactly what level the coolant reserve tank was but it wasn't low enough to be noticed. I did two sessions pretty relaxed just to get comfortable w/o incident. My 3rd session I went balls out for ~20-25 min; after bringing the car in to cool down, I popped the hood, heard hissing, and realized that the coolant in the reservoir was bubbling and boiling, with coolant escaping from around the fill cap. I checked the temp gauge and it was just 1 or 2 bars shy of red. The motor was still running, and I cranked the heat all the way up on the climate control and waited a bit. Eventually the gauge hit red, so I killed the engine. Took a while for the coolant in the tank to settle down, after which I could see that there wasn't really much left in there, the radiator was low, and a bunch of coolant had splashed out in the engine bay both while I was driving and afterwards (presumably from around the fill cap because I couldn't see any other leaks).

I borrowed some 50/50 solution from someone else and refilled the radiator up the top (it took a lot of coolant) and maxxed the reserve tank. Unfortunately, at the time I didn't know about bleeding the system; sorry I'm lame... clearly at this point there would have been air in the system.

So I took the car back out and kept an eye on the temp gauge. After a little while it started creeping back up so I brought the car back in and popped the hood. The coolant in the reserve tank was boiling again, but I left the engine running with the heat blasting and eventually it cooled back down to 3 bars. The reserve tank fell down to MIN, and I filled it back up to Max... the radiator itself was still full.

I then decided to pack up and go home. I drove back home, which probably took about 3 or 4 hours in some heavy LA traffic. The temp gauge never went past 3 bars, IIRC but def not over 4 bars.

I did some research, then went out to work on the car. The reserve tank had fallen again about to halfway. I went to bleed the coolant system... coolant came out almost immediately from the first valve. Should have clued me in, when I did the one against the backwall... let's just say I'm glad I was wearing eye protection since a bunch of coolant splashed out. So, appears there was NO air in the system at that point. Perhaps it was all burped out while I drove home?

So, my question is... what happened? What should I check? Do I need to get a pressure test? Maybe there was air in the system even though the reserve tank was full before I wrung the car out? But doesn't the coolant system eventually burp out the air (I put over 10K miles on the car after buying it w/o incident until now)?

I do have HondaCare coverage on the car, so I could take it in under that... but (1) hypothetically speaking let's say I have a Spoon thermostat, would they try to deny my claim based on that? and (2) would hate to get hassles from them on my "spirited" driving. FYI, hypothetically I have a Spoon throttle body but rest of engine is stock.

I'd appreciate any feedback or suggestions. TIA.

Ludedude

Steve, was this the same spirited driving day where I was a few weeks ago?

SSK

Indeed it was JP! Despite this problem, I had a blast, and didn't even need to use that fancy new tow hook. Did you see the pics I posted in the SoCal forum, not sure if you were in there.

Do you have any thoughts on the overheating issue? It was damn hot out there, but I checked two nearby S2Ks and they were only at 3 or 4 bars on their temp gauges.

Ludedude

I had some coolant spew from the overflow bottle that day as well, but didn't see the temps fluctuating the way you described. I didn't lose enough coolant to have the bottle empty or have to add more. I never actually saw more than three bars on the temp gauge. My cooling system is still stock with the exception of a different mix of water/coolant additives.

Offhand, I'd say you didn't damage anything. Since you did the right thing by shutting the car off when it got to the top of the gauge and it's been running fine subsequently, I wouldn't worry about it too much. Keep an eye on the coolant level and also check your oil for signs of coolant (which would indicate a potential head gasket failure) but other than that there's nothing I would suggest. Maybe someone else has a different opinion on the matter, but that's mine

I saw your pics in the SoCal thread BTW, but none of them were of me

J.P.

solid

When was the last time the thermostat was looked at???
That would be the first thing I look at. Its a very cheap device that results in majof f*** ups when not working proper.

Scot

I had overheating problems that was for sure an airbubble..... open the bleeder valve and that other little goofy cover thing by the firewall and fill the radiator until it starts to squirt out of both of those....then you know for sure you have no airbubbles......

basically my car was not moving the liquid so the stuff in the engine would get super hot, but the radiator would stay cool and the fans wouldn't even come on...... once the guys on the internet (and a local mechanic) pointed me to the bleeder valve and the other thing my problems were solved.

Road Rage

Thermostat in my opinion. They are of the wax pellet type, and the springs can degrade as well - they can open and close on ya.

Have you serviced the coolant? It might be old and gelling.

Ludedude

Hmm, yeah. A coolant service/thermostat replacement might not be a bad idea and is good preventive maintenance.