Over heating question..

[Ellen]

Long story short.
Brand new Jasper Engine installed 5 years ago.
less than 100 miles on engine.
Now when I try to drive the car it runs hot less than 1 mile from my house.
I am pretty sure the fans are running, I hear at least one running at idle in driveway.
Typing this in I am thinking, flush system without thermostat and then install new coolant and thermostat as first step.
Am I on right track?

Sorry,
Hi,
I am Ellen,
long time owner just don't drive as often as I used to.
1990 Vette with 60,000 original miles.
Trying to decide whether to sink money into this car or to sell it.
I am here for repair advice and possible selling information.

 

[vigman]

Hi Ellen

First things first..
Car has been garaged through it's long sleep?
Does the overflow have coolant in it?
If yes... if you start the car, let it come up to temp ( idle in driveway) are you leaking underneath ?
Did you look at the air intake under the nose to see if somethings blocking air flow ( news papers, plastic bags, leaves, mouse house ) ?

Sitting for this long is not great..... for any car...

Mike

 

[Ellen]

We know prolonged idleness is not good.
Clogs fuel lines, injectors, gas ages...
Very ugly situation.
Life through us a couple of curves and that is why sleeping so long.
Last time I started it there was no leakage.
I can answer the fluid level question when I get home but I am betting at this time it is dry.

 

[vigman]

Steps

And what is "HOT" did the gauge go 240 260 hit the pin ?

1) Top off the overflow& the surge tank with 50/50 coolant.. take note how much you have to put in to get it full... ( don't cap it... yet )
(Note here 90's on up, to the best of my memory do not have a conventional cap on the radiator, we're trying to confrm the cooling system has coolant )

2) Start car let it idle.. keep eye on coolant rez, turn heater on...

3) As the car approaches 180 degrees cap the overflow... shut car off..

4) Check air intake on front of car, look up, underneath nose check for STUFF....

5) Wait for 10 or so minutes pop rez and see if the coolant went down again... top off as needed..

6) Cap system, let the car idle again at about 220 deg the fans should come on... USE GLOVES...If the cooling system is holding pressure the upper radiator hose will be firm... if the hose can be easily squeezed, you still have air or a leak somewhere...

7) If everythings OK ( and the car is stock ) the temp should drift between 200~215( ish )....Note if hot air is coming out of the heater ducts.

If the temp starts to climb past 225~228 shut it down.
I assume the car is on level ground?
Is it in a garage?

8) if you can , put some clean cardboard under the car's engine bay... and see in 30 min if you have leaky leaky....

Mike

 

[John Robinson]

Going along with vigmans suggestion. The seal on the radiator cap is old and dried out you may not be building pressure because of a bad cap. Pressure raises boiling point. A bad cap also will not allow a vacuum to build up when cooling down and so it won't siphon fluid back from the overflow tank. It just may be this simple. Mickey and Minnie like to set up housekeeping in tight spaces like between the radiator and Air conditioning condenser. Your next issue after you getting cooling maybe to pull the fuel pump and check it for rust and and replace the inline fuel filter.

 

[Hib Halverson]

When you say the car "runs hot" exactly what do you mean?

Does the cooling system boil over?

If one fan comes on, turn on the A/C and see if the second fan comes on. Does it.

Let the engine cool and check the coolant level. Is it full?

 

[SnakeDr]

Did you replace all the hoses? I must of had a pinhole leak in one of my hoses and sprung a leak in February.

 

[Ellen]

Try to reply to all..
Fluid level was good.
Not leaking.
Not boiled over.
Tried driving couple of times needle came close to pegging super hot so I turned around and came back home.
Different times let idle in driveway with motor running at 1500 rpm or so, at least one fan running, temp gauge would climb and engine would shut off.
Did replace cap a few years back, unknown exactly when.
Should so again, cheap fix.

 

[Hib Halverson]

Ok...
The good news is that while your engine may be running hot, it is not overheating. As for how hot it's getting–that's tough to determine because 1) the IP gauges on late C4s are inaccurate and 2) a 90 does not have the ability to display engine coolant temp on the IP display by pushing a "gauges" button. I believe that feature was not added until 1992.

If you have a scan tester, you can connect it and read the true ECT.

You said earlier that one of the cooling fans was working, but didn't say if the both were working. With the engine running and the temperature headed upwards, turn on the A/C and check and see if both fans are on. If not, the next thing to do is run the cooling fan diagnostic procedure in the Service Manual to determine if you have a problem with the cooling fans.

Lastly, did you say that the engine stalled once the temp gauge got near the high end?

 

[vigman]

Some points

Try Hibs turn the AC on... and see if the temp drops...
Did hot air come out of the heater ducts?
Did the top hose get firm? ( under pressure ) ?
Did you check both tanks ( overflow & the one by the firewall) ?
What color/ condition is the coolant?
was there anything up in the nose ( bags, leaves, Jimmy Hoffa ) ?

If I had to guess at this point, I would replace the stat.....

Mike