EJ251 overheated then cooled back down

[unsullied_spy]

After getting off the interstate tonight and stopping at the light, I looked down and saw my temp gauge was up to 3/4 or more and then as I pulled away from the light to get to a safe place to shut down and roll the car started cooling back down again. The engine temp was perfect while it was driving (80-90 MPH through a mountain pass, if it were a water pump or radiator I suspect it would have cooked in the canyon) but once I slowed down the temperature started to rise. I have just shy of 80k on the car, and around 74k miles I had a ton of work done to the car including upper and lower radiator hoses (Gates), new thermostat gasket, head gaskets, water pump (Paraut), new main cooling fan (some PoS TYC part from Napa that I had to disassemble and frankenstein onto my old mount and blade but it works), and a bunch of other stuff. I pulled into a gas station to fill up and check everything out and the coolant level was perfect, maybe 1/4 inch over the hot full line, and the fuse for the cooling fan was fine. For the record I don't believe the fan was on when it overheated, the thing is so loud and makes a slight vibration through the car I can tell if it's on at idle. Everything checked out fine so I drove it 11 miles home and absolutely nothing out of the ordinary. Any ideas what could be the cause? The Radiator, T-stat, heater core, and heater hoses are the only parts of the cooling system I have not yet replaced yet, I'm wondering why it wouldn't overheat pushing 80+ through a mountain pass :-?

Off topic, but a little concerned: When my cooling fan went out the engine went up over the line before it turns red (normal temp is between 2 lines around the halfway mark, it went up above the line above normal. I wouldn't say it hit 7/8 but darned close). I replaced the fuse and drove it for another 2 days and it went up a little above that second line before I noticed and shut the engine off, now it's gotten hot again. As many troubles as I've had with this car and as notorious as these engines are for blowing head gaskets and warping heads how much trouble am I in with my engine right now?

[96LegacyWagon]

I would probably check to make sure you have enough coolant in your system. When it is totally cooled down pour new stuff in until it reaches the top, then squeeze the hose gently a few times, and add more until full. Repeat as many times as needed to get the system really full.

If you have a leak, find the source (UV dye would probably do the trick if you have access to a blacklight). If not, then check your density with a hygrometer (sp?) to see what temps your coolant will go to before freezing/boiling over. And... if it was a long distance overheat you may need a new thermostat as well.

[unsullied_spy]

Coolant level is normal. This was after a ~2 hour drive on the Interstate running 80-90 and right before I get back to where I live there's a several mile long mountain pass which I didn't really slow down for so the engine was definitely working and you'd think it would overheat then if anything. The temperature was perfectly fine until I stopped, then it started climbing back up. I'm wondering if the thermostat got pushed farther open from being pushed harder than normal and then somehow closed too far and got stuck closed too far. The temperature started going down as soon as I hit the gas to get to a safe place to shut down, which would spin the water pump faster creating more pressure against the thermostat (maybe this would push it back open again? I'm guessing here). I'm on the stock thermostat at just shy of 80k miles. It's been nearly a week and under normal driving conditions the temperature has been normal. I did take it out on a back road and did a WOT 0-100 pull then got on the brakes real hard to limit the air cooling and I thought I saw the gauge go up a little over it's normal spot but nothing really significant.

[Wiscon_Mark]

Thermostat. Replace it with an OEM one, no aftermarket!

[unsullied_spy]

OK. I'll give that a shot when I get paid. Is it OK to catch my old coolant in a drain pan and run it through a coffee filter or something and put it back into my radiator? I flushed my coolant about a year and a half ago, my water pump blew about a year ago, then a month and a half after that my head gaskets were done. I'm kinda tired of spending money on coolant...

[Wiscon_Mark]

Heh, I wouldn't take any chances with how temperamental the headgaskets can be.

[jjay03]

How old is the radiator cap I would replace it if its older. I would get the OEM cap too.

[unsullied_spy]

It's the original cap. Can't hurt to replace it as well I suppose. Do the OEM ones come with the warning sticker on them (yes, I am that OCD)?

[jjay03]

It's the original cap. Can't hurt to replace it as well I suppose. Do the OEM ones come with the warning sticker on them (yes, I am that OCD)?
Yes they do in Japanese too! If its original I would replace it for sure. Mine overheated before and spilled coolant so I bought a cap and new thermostat. I replaced the cap first and its been fine since I still have the new t-stat on my desk.

[unsullied_spy]

It's the original cap. Can't hurt to replace it as well I suppose. Do the OEM ones come with the warning sticker on them (yes, I am that OCD)?
Yes they do in Japanese too! If its original I would replace it for sure. Mine overheated before and spilled coolant so I bought a cap and new thermostat. I replaced the cap first and its been fine since I still have the new t-stat on my desk.
Awesome! Thanks for the advice.

[jjay03]

Guess what mine overheated again and its been a few months since it did last time. Im afraid its my HG but im going to try the t-stat since I have one.

[unsullied_spy]

If your coolant or oil starts looking like a milkshake and you're losing coolant then it's head gaskets. Hopefully it's something more simple than that. I pulled my old radiator cap off and could not press the plunger in more than maybe 1/8 inch, put a new one on from the dealer and did a WOT 0-100 run and the temperature gauge never moved. I'll replace the T-stat before my next trip but for the time being it's running perfectly.

[jjay03]

Yeah I hear they can do weird things sometimes. Im going to try the t-stat but I still wouldnt trust it to go on a long trip.

[Staxta]

Coolant level is normal. This was after a ~2 hour drive on the Interstate running 80-90 and right before I get back to where I live there's a several mile long mountain pass which I didn't really slow down for so the engine was definitely working and you'd think it would overheat then if anything. The temperature was perfectly fine until I stopped, then it started climbing back up. I'm wondering if the thermostat got pushed farther open from being pushed harder than normal and then somehow closed too far and got stuck closed too far. The temperature started going down as soon as I hit the gas to get to a safe place to shut down, which would spin the water pump faster creating more pressure against the thermostat (maybe this would push it back open again? I'm guessing here). I'm on the stock thermostat at just shy of 80k miles. It's been nearly a week and under normal driving conditions the temperature has been normal. I did take it out on a back road and did a WOT 0-100 pull then got on the brakes real hard to limit the air cooling and I thought I saw the gauge go up a little over it's normal spot but nothing really significant.

I had the exact same issue, if you're still having the problem, for me it was air pockets within the coolant (it appeared full).
After burping the system on an incline and adding more coolant it's been fine for 600km+.

[jjay03]

Thats what I think mine is but I think it might be cause the HG is starting to go. Im replacing my T-stat this week though once I go get another gasket.


Coolant level is normal. This was after a ~2 hour drive on the Interstate running 80-90 and right before I get back to where I live there's a several mile long mountain pass which I didn't really slow down for so the engine was definitely working and you'd think it would overheat then if anything. The temperature was perfectly fine until I stopped, then it started climbing back up. I'm wondering if the thermostat got pushed farther open from being pushed harder than normal and then somehow closed too far and got stuck closed too far. The temperature started going down as soon as I hit the gas to get to a safe place to shut down, which would spin the water pump faster creating more pressure against the thermostat (maybe this would push it back open again? I'm guessing here). I'm on the stock thermostat at just shy of 80k miles. It's been nearly a week and under normal driving conditions the temperature has been normal. I did take it out on a back road and did a WOT 0-100 pull then got on the brakes real hard to limit the air cooling and I thought I saw the gauge go up a little over it's normal spot but nothing really significant.

I had the exact same issue, if you're still having the problem, for me it was air pockets within the coolant (it appeared full).
After burping the system on an incline and adding more coolant it's been fine for 600km+.

[jjay03]

Starting to see more bubbles in my overflow I might check it out some more tomorrow. Sure ill have to do HG's soon though. Is there a how to thread somewhere on the HG replacement with everything ill need?

[unsullied_spy]

Starting to see more bubbles in my overflow I might check it out some more tomorrow. Sure ill have to do HG's soon though. Is there a how to thread somewhere on the HG replacement with everything ill need?
If you buy a complete head gasket kit (probably run $300+) it will come with a whole assortment of gaskets to replace while you're at it. It's best to remove the engine from the car to make sure you get the block and heads properly cleaned up for the new gaskets. It's recommended to use a bristle brush and some surfacing discs to clean up the carbon buildup and whatever else builds up around the seating area for the head gaskets before putting new ones on. I work at CarQuest and have access to a database with some repair specs in it, I'll try to remember to print off the pages regarding Head Gasket replacement, scan them, and post them. When my gaskets went I was able to order in a whole kit from Ishino (OE supplier for the head gaskets) which included cam seals, oil pump seal, valve cover gaskets, spark plug tube seals, intake gaskets, exhaust gaskets, etc. which made the whole job really easy. Pretty sure walk-in price on that kit is about $330 though, but it includes almost every seal in the whole engine--go big or go home! Mine is paid for and only has 82k miles on it, the soonest I have ever sold a vehicle was 180k and I want this to go at least 300k before selling it, a penny spent is $10 saved :cool:

[jjay03]

Thats what im looking for a whole kit and I want the best head gaskets. I will be pulling the engine and cleaning everything up for sure.

[unsullied_spy]

That's good. I printed the directions for resurfacing the heads and block, actually getting the engine out and apart as well as torque specs for everything is probably in the FSM, I can print you mine but it's for the SOHC.

[unsullied_spy]

http://www.scribd.com/doc/95783900/Cylinder-Head

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[jjay03]

Cool thanks