jrockw01

89 L98. Recently had the head gasket replaced and generally running great. Only issue I'm having is that at highway speeds 75-80, it gradually builds up oil temp to 218-220 or so. It used to run rock solid at 210 or below. Coolant stays pretty steady at 195.

At 60-65 it runs regular temps. Idle temps are fine even in high external temps, coolant fans come on when they are supposed to etc.

Only other minor issue I'm having is that it is a little hard to start cold. Have to crank it once, then the second time it usually catches right away. Warm start is fine.

They shaved the heads, would the additional compression cause temps to go up this much?

Any thoughts on anything else to check? Its not throwing any codes.

TR Vert

I'd start with the simple stuff.
Have you checked between the condenser and the rad to make sure that you have not recently accumulated some road trash in there?

Trash restricting airflow is the #1 cause of overheating.

jrockw01

Yeah, I had them clean that out when they did the head gasket.

CFI-EFI

You have no temperature problems. Your temps, both coolant and oil are great. Your oil temp went up 8° to 10°? BFD! It is still way under any critical numbers. My oil temp often runs 235° and I am totally unconcerned.

For your cold start situation, check your fuel pressure. See if it bleeds off over night. See if jumps up during the priming period, and check to see how long it holds pressure after the engine is shut off.

RACE ON!!!

TheCorvetteKid

How long should the fuel system hold pressure? I've always had a hard-starting issue with my '89 that I've never been able to pin-point (I've just gotten used to it and pretty much ignore it now). I'm just curious if this might be it.

Didn't mean to hi-jack the thread.

jackdaroofer

Not to doubt anyone, but are you really sure they pulled the top shroud and if enoulgh trash was in there, even the radiator?

While others have said your temps are fine, speaking personally, I would not be happy with those temps

Even on the hotest days, at speed, my coolant hardly exceeds 175 and oil around 185 to 190 and I am talking about driving 100's of miles. I use a 160 thermo in summer and switch to a 180 in winter. I also have the switch that turns the auxiliary fan on at 205 deg

At Idle, or stuck in traffic, my coolant will run into the 200-210 range and oil into 215-220, but once I get rolling again it drops back

I found that I had to pull the Radiator and clean the honeycombs with air and soap and water and I also installed new spoilers since mine had a lot of curb damage

Just some thoughts IMHO

seeya

CFI-EFI

Now THOSE are temperatures to be unhappy with.

RACE ON!!!

Lichen

I agree. He said that his oil temps were running a bit higher, not his coolant temps.

theadmiral94

jrockw01,

has the oil & filter been changed with the correct & same oil & filter at least twice since the head gasket was change (1st time should have been after the engine was re-assembled but before being started)?

Is the oil pressure the same as it was before the head gasket at all RPM's?

Might some gasket material/dirt/etc from the head gasket change be slightly clogged the oil pick-up screen in the oil pan?

It sounds like less, contaminated, different or the wrong oil (weight, non-synthetic) might be moving around in the engine, thereby increasing its temp.

Hope this helps...

MrNuke

In the humid 90-100F days here in CT lately, my vette gets up to 220-225F (OIL) on the highway, and 205-215 Coolant. If I get on her a little, she peaks at 230's (OIL), 220 Coolant. This started since the Headers have been put in the car and the new tighter tranny/2400stall TC). I am also running an SLP ram-air system which sits in front of the radiator, sucking in about 75% of the air instead of letting it cool the engine.. But I am not worried. Car still runs like a beast, and when in town with the fan on, normal driving, it rarely gets above 210(OIL), 210(coolant)..

I am running a 180F thermostat.., and my coolant could probably use a change..

Slalom4me

I agree that the current temps aren't an issue but like you, I'd
be interested in an explanation for the increase if it was my car.

Good points to check out. Hopefully, the shop was conscientious and
there is not any debris blocking the pickup. Changed oil viscosity
sounds plausible. GM recommended 5W-30 for the '89 L98. If the shop
put 10W-30 or 20W-50, you would see it on the pressure guage and
temps would go up at RPM. Call to ask what they put in.

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