Overheating Problem

[jjtarnow]

I have a 514 with an oil cooler, 3 fans (2 small push and 1 large pull), with an aluminum radiator. I have been using Evans Waterless coolant and have always been able to keep the motor under 210 (max) even on hot days. All of a sudden the temp has started to just climb as though it has no fans running. Once I move the temp is under control (as you would expect). If I sit at idle the temp will climb out of control. All the fans are working fine and the coolant level is fine. I would imagine the only other two items to look at would be the water pump and the thermostat. Any suggestions would be greatly appreciated!

Josh

[mr0077]

Josh, if it was okay, with no recent changes, and it cools okay at speed, I don't think it is the pump or Tstat, it is an airflow issue, or maybe that with an air bubble in the system...has the system been opened or gotten low on fluid recently? Might check for air...bleed the system at the high point.

[jjtarnow]

No recent changes...air flow is the same as it was when it was working well. I guess I will try the system bleed (which I didn't want to do as the Evans cooling stuff is expensive).

[TedMiller]

Check the radiator cap. Pressure test it. Use high pressure cap, 12-15 lbs. An engine will run hotter if the cap is weak.
Ted.

[byron w]

Josh,
Might try pressurizing the cooling system and then pull
the spark plugs one at a time to confirm you don't have a head gasket leaking a little.
Good luck
Byron

[ByronRACE]

There's a little test kit you can use to test your coolant for the presense of combustion gasses. Like this:

http://www.etoolcart.com/index.asp?P...OD&ProdID=1687

If you don't have a head gasket problem, here are other possibilities:

- Trapped air. If for whatever reason air becomes trapped in the back of the heads/engine, it will create an air pocket that won't necessarily find its way out of the engine. The back of my intake manifold is drilled/tapped for this reason, and twin lines run forward to the water neck allowing a little coolant flow to bypass the heads and keep this area clear of air pockets. You could try jacking the nose of the car high and running it; that might help.

- Stuck thermostat. Thermostats do stick; and when they do...you could overheat.

- Fan wiring. Is it possible you have your pushers and pullers working against eachother? Try powering each fan individually and make sure they're all pushing air from nose to tail through the radiator core.

- Collapsed lower hose. Is the lower radiator hose collapsing when the thermostat opens? Weak hoses with no internal spring reinforcement can do this; and when they do, coolant flow stops. Also, I've seen internal plies of multi-ply hose collapse leaving the outer shell looking OK. This failure mode will drive you to drink.

- Timing retard. Is the timing advance grossly retarded? Did someone accidentally time the engine ATC instead of TDC? If so, the additional retard will create a ton of combustion heat.

- Water pump. Did the impeller seperate from the shaft? Seen that. Pulley is turning; impeller is not.

Hope some of that might help.

Byron