Overheating issue

RLUSTO

MEMBER
2002 HONDA CIVIC
1.5L
4 CYL
2WD
AUTOMATIC
189,000 MILES

My engine keeps wanting to overheat, or at least temps reading hot (between half and three quarters up gauge)
Seems to mostly happen after traveling at higher speeds.

Recently (several months ago) had to replace radiator due to low coolant and overheating.
A friend of mine checked it after initial overheat, but did not pressure test, said "it is fine, you were just low on antifreeze" then it overheated again three days later on the highway, this time shooting antifreeze out the front of radiator.
Old radiator busted, so has new one put in.

Since radiator has been replaced, still having consistent issues with car wanting to overheat.

It seams to only happen after I have the rpm over 3000 for a few or several minutes, then when I slow down, the temperature gauge starts creeping up. Usually turning on the heat will help it from going all the way up, but it keeps fluctuating up, then down, up, then down.

In trying to figure out what is causing this issue,
I have replaced:
Radiator (CARQUEST radiator.
Part No 431480 @ Advance Auto.
Radiator cap(one that came with radiator busted somehow).
Overflow housing (got a hole in it and was spewing after pressure built up in system, this was after pressure test showed no issues)
Timing belt (maintenance).
Water pump (maintenance, but also cold air blowing at idle when heat was on).
Head gasket (because nothing else worked).
Repaired warped head (machined because it had gotten warped due to overheating).

Any ideas what could be the fix? Being as I just dropped $1,000.00 into it, was hoping to keep her for another year or so.

8 Replies

RLUSTO

MEMBER
9 POSTS

Oh and also the thermostat. First a cheapo, then a more expensive one I was assured would not fail.

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Thursday, April 6th, 2017 AT 5:50 AM

HMAC300

MECHANIC
48,601 POSTS

Was the head gasket put on correctly as they can be put on upside down or backwards? Check the ground for the gauges and battery to body ground it may not be grounding. And radiator that was put in was it the correct size along with cap? One other thing was cylinder head checked for flatness? It could be warped causing a head gasket leak. Should be with in.003". Also, check for lower radiator hose sucking together when you rev it up or bulging that may be problem.

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Thursday, April 6th, 2017 AT 6:07 AM

RLUSTO

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9 POSTS

The gasket was just changed and head was warped but has it machined to cut off like 1/16000 of whatever measurement they use. By checking for gauges and battery ground, this is confirming gasket was installed properly?

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Thursday, April 6th, 2017 AT 6:36 AM

STEVE W.

MECHANIC
12,997 POSTS

Okay you are running the engine up at high rpm and when you slow down the temperature goes up correct? That would be normal as the cooling system still has a lot of heat in it from the higher speeds and now it has lower airflow when you slow down.

You say you are using the stock gauge, Install a real temperature gauge and see what the temperature really is. You could be getting all upset over a bad sending unit or bad gauge in the dash.

As a precaution a pressure test and combustion gas test to help rule out a wrong/bad head gasket install.

Also, an exhaust back pressure test, As you had a bad head gasket once and it did overheat it could have started blocking the converter and that is holding the heat in the engine.

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Thursday, April 6th, 2017 AT 6:59 AM

RLUSTO

MEMBER
9 POSTS

Had thought of that, but it is definitely loosing antifreeze somewhere, because after gauge runs up, it is always lower on fluid.
At any rate, will do as you suggest, as well as the tests ASAP and get back with my findings.
Thanks!

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Thursday, April 6th, 2017 AT 7:10 AM

RLUSTO

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To clarify my post before, this problem has been "consistent" through all repairs mentioned above, but is intermittent. Like I said, only after going over 300 rpm (i.E. If I keep it under 70 mph, usually no problems) So, mostly after being on the highway for a while, then it will act up. Maybe something to do with pressure building up? I do not know, I am not a mechanic and also do not do my own work on the vehicle. No visible leaks. No mixing of fluids. Had all those other components replaced. Should no longer be overheating.

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Thursday, April 6th, 2017 AT 7:24 AM

HMAC300

MECHANIC
48,601 POSTS

No by checking ground you may not be getting a good ground for gauges to work properly causing the fluctuation that you say you have. Also checking for bulging/sucking hose on bottom of rad may sucking together getting poor flow to engine. Only way to check for head gasket installed wrong is to take head off but I do not think that is it.

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Thursday, April 6th, 2017 AT 10:24 AM

STEVE W.

MECHANIC
12,997 POSTS

I agree with HMAC300, it does not sound like a gasket installed the wrong way. It sounds more like a crack in the head or block that is opening when it gets run hard. That will make it harder to find because it could be sealed while not under the higher heat and temps. Pull the spark plugs and use a camera to look at the pistons, if you find one that is very clean or a plug that is cleaner than the rest it could be from coolant leakage into that cylinder.

It is possible it is heater core related as well, you could have a minor leak that only opens under higher pressure/temperature, then it leaks out the A/C drain and evaporates. Maybe throw some UV dye in the coolant, run it hard and look for traces in the exhaust and the AC drain.

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Thursday, April 6th, 2017 AT 11:30 AM