germanspeed

Hey Guys,

Can anyone tell me why my 91 C2 will not hold temparture to save it's life??? I never gets above the second mark on the gauge...7 o' clock postion i guess. I know that it is just starting to get warm but I am nevervous about the oil level and i can't get it warm enough to get a good reading. Anyone else face this issue?

dfinnegan

Some folks put a blanket over the rear grill in order to get the temp up to ~9 o'clock in order to check the oil level.

Bottom line, the level should be checked at the typical operating temperature for your car and environment. If you are going to go out and thrash it and bring the temp up you should not be checking the level at a lower temp or you'll risk overflowing into the intakes.

Here in NY, USA I can typically get up over the 8 o'clock mark by letting the car idle for a while.

Cheers,
Dave

Edit: of course, you really must get the temp up to where the t'stat opens, at least, in order to check the oil level

Streetfighter

Your oil level for driving should hover around that third notch close to the middle, but should be just below. If you want the temp to rise start up drive it for 15 minutes. Stop on level surface and let it run for a few minutes that should open up the thermostat and give you a solid reading.

John Boggiano

These aren't like water-cooled engines - as you increase the revs (even when stationary) you increase the cooling. Just let it sit at idle for a good while and you'll see it climb.

jimq

you dont drive in Florida much do ya. Those are winter temps around here

dfinnegan

The third mark being the 90C (194F) mark in the pic below.

The thermostat should open just a bit below that mark (88C IIRC), then you'll see the needle drop a bit as the cold oil from the front lines blends in. After it comes back up again you are getting in the right range for oil level checking. I like to check the level a bit above the 90C (194F) line as I will see all of that around here in the summer time and sometimes get above the 9 o'clock range.

kurquhart

Thermostat could be stuck open.

tbennett017

Also check in this sequence:

Feel the passenger side fender, along the top. If it is hotter in a region above the wheel, your thermostat is open. Then listen/feel to see if you feel the fan running below and in front of the left-front tire well. The failure-mode of the fan resistor is to go on full-time.

You could have one, or both of those situations going.

Is your A/C on? That will also kick on the fans on both sides.

Streetfighter

I have no doubt about that!

mongrelcat

Can you elaborate on what you mean here by "oil from the front"?

Very interesting. Is this the same with a 993? I have noticed this drop after hitting the second mark 90C (194F) (~8:00 o'clock) on the gauge. Where I am the ambient temps now are around 45*, and when I see the drop it's usually two or three needle-widths, then it pops back up to ~194F after a few minutes.

While messing around and trying to figure out the oil level gauge and such on my new-to-me 993 I warmed up the car well, and then let it idle for 15+ minutes. The oil temp went to ~245F and the level indicated on the gauge and the dipstick both registered significantly higher than just a half hour earlier when the car was at it's normal ~194F.

dfinnegan

By "Oil from the front" I meant the cold oil from the piping beyond the closed thermostat.

There is an oil cooler in the front right fender that helps cool the oil after the thermostat opens. When cold, the thermostat is closed and this front loop is closed off. When the thermostat opens the cold oil in these two lines, up, and back, is pulled into the system and lowers the temp of the oil that's been circulating through the engine.

Oil expands when it gets hot. That's why you need to get the engine fully warmed up to check the oil level.

mongrelcat

Thanks for the reply. I probably should've done some digging on my own before asking such a basic question, but I do appreciate the clues.