Mike mike

I have a 88 C4 with mods. The car will run a engine temp of around 185-200 on the highway at 70 MPH on a 90DEG day. This is with the stat removed. In traffic it will go to 210-215 Deg. If I have the AC on it will go to 235-245 Deg in traffic and 215-220 Deg at highway speeds. I know that with these temps are ok and will not harm the engine. What I want to know is what kind of temps are other guys getting with their L98's. Mods or stock. And if anyone has the T-stat removed from their engine what are your temps? Also how hot is too hot for oil temps? I run Mobil 1 and my oil temps are 200-215 Deg. All the time.

mikey whipreck

1985 L98

185-195 while crusing
195-215 while idling

stock tstat (196), stock fan settings (225/238)

Oil temps hang around the coolant temps.
Mobil 1 with engine-restore

kdf1986

I have a 1986 all stock engine parts.

Temp will stay between 200 and 220.

kdf

jimmers

90 mostly stock. Driving around 170 idling 200-220.

toroguy

I had the same worry when I first bought mine - the temp was higher than one would expect...the digital guage makes you more aware of the temp than a generic needle guage without numbers like in most cars. At least thats my theory...

Same temps on my stock 85 as others mentioned.

olefam

1991 coupe here. The "new" dash doesn't give any numeric values. Nor does it have a linear guage. Consequently It's anybody's guess what the temps actually are. I HOPE the fans come on when they're supposed to. My thermostat is a new GM part set at 196* So far everything seems to check out ok when I bring it in to a mechanic for various work.
Analog guages are great when they actually provide information. Not worth a fig when they're just for show.
Glen

Chance

I've seen oil temps as high as 270.

230 is not uncommon on a hot day.

If you're oil temps are 200-215, you've got no problems.

vader86

Your temperatures are normal, but do not ever run the car without a thermostat, it'll cause cavitation in the WP.

With aluminum heads, dont ever let coolant get to the 250-260 range. If it does then pull over immediately and let it cool.

If its M1 synthetic oil, then the oil can handle 300F.

Demonic85

The highest my engine coolant and oil temps have ever reached was 200 degrees F. Might be cause it has a new water pump and all that good stuff when I bought it. It does go up pretty fast sitting in traffic.

mikeb

New (er) 185 degree thermostat and temp switch;
185-190 degrees at cruising speed.
230 max at idling/city driving in traffic, will drop to 210-220 when fan comes on.

rick lambert

stock 87
180 thermostat and with VADER and have a few more reasons..but, I'll save that.

2 fans, main and aux. both wired to a lower temp switch to come on at the same degree 200, and off at 185.

at idle or in stop and go temps will reach a max. of 210
cruising temps are 175-180..

oil temps reach around 200.

vette_tweak

My 383:

Ambient: 77 DEG F
Highway, oil = 185, coolant = 167
City Traffic, both 194 max

That's with a 160DEG thermostat and the chip kicking the fan in at 160DEG.

FYI, I've noticed that roller rockers will drop the temps by about 10 to 15 Deg F. This is a direct apples to apples comparison by only changing to/from roller rockers . Found this out by coincidence...I was going to sell the car so I removed my expensive CompCams rockers and the running temps increased.

I've also noticed that oil age makes a difference. I use Mobil 1 10W30. I know when it's time to change the oil by the oil-to-coolant temp differential on the highway. As the oil becomes "old" ( contaminated with gas I suspect), it doesn't transfer heat back into the motor as quickly. Normal or "new oil" differential is 18 DEg F, ready to change oil differential is up to 33 DEg F!

rick lambert

I find that extremely odd about the roller rockers.

vette_tweak

I think it's quite intuitive... friction reduction = oil temperature reduction

from Crane:

Needle bearing fulcrum and roller tip reduces friction, lowers engine oil temperature, improves response, increases HP and RPM.

crawfish333

This topic has been discussed here many times. The digital temperature readout on the C4 is somehow scarier to most of us than the analog gauges. Sometimes when I am driving my C5 in hot weather I'll look at the temperature gauge, and she'll be hitting the 225 degrees range and I'll never give it a second thought. When I see the numbers on the digital readout on my C4 hit 225-230, I get concerned.

I would make sure that you radiator is clear of debris because this can be an issue on C4s. I would also flush your radiator if it has not been done recently. Your temperatures all sound normal, but IMHO I would try and step down the 245 a bit. Also, I was under the impression that the car actually would run cooler with the A/C on because the fan will run constantly. If you are really concerned about making the C4 run cooler, you can do what a guy in our club did with his:

He installed a 180 degree thermostat and he rigged the fans to stay in constantly. He also built an aluminum spoiler under the radiator. If you keep good coolant and make sure you radiator stays clear of debris, all this should be unnecessary.

ken y2k c5

My temps have been running high. I am pushing 260 after about 2 hours of constant driving. I'm sure there is a problem though.

starky

1989 L98 stock 200- 210

DoodleD

Cruising 170-190
Idling 200-220

auger58

In traffic on hot days my coolent temp can get up to 240 but oil temp may only go up 5-10 degrees.

Midnight 85

I'm sure you are right, that would scare he11 out of me!

Mike mike, never ever run without a stat, not only will it cause cavitation in the pump but the water is flowing through the radiator so fast it doesn't have a chance to completely cool. If you have mods you probably have a chip which calls for a 160 stat like mine does. Put a good one in such as a NAPA.