overheating

[tubz]

I have 1983 monte carlo SS, with a high output 305. I just had a mild lift cam installed and now the temperature goes from under 200 degrees at an idle to 280 degrees when running at 55 MPH. This didn't happen before the new cam, always ran around 200 degrees. Tried changing the thermostat and added a mechanical temp guage, always the same result. high temperature. Any ideas.

[bobss396]

Was the manifold also changed, obviously it was off the car for the cam and lifter job. I can only think of a couple of things off hand.

Check the timing first, it should be fairly close to stock specs. Badly retarded timing will cause overheating. Another is when the manifold was put back on, did they block off any of the ports that run under the carb? Some intake gasket sets had these little metal plugs that would block them off and could cause overheating for the wrong application.

As a last resort, make sure your radiator hoses are not collapsing, have your radiator cap and cooling system pressure checked, make sure your fan belt is not slipping, did they reinstall your fan shroud?

It has to be something very basic, good luck.

Bob

[richtazz]

A few questions:
1. Did you install the cam straight up, or did you install it with a multiple keyway timing set advanced or retarded?
2. Did you check for vacuum leaks?
3. Are you still running the factory ECM, and if so, what are the cam specs?

[Rally Sport]

Maybe you need to get a better cooling radiator or water pump to cool it down quicker.

[tubz]

Originally Posted by Rally Sport

Maybe you need to get a better cooling radiator or water pump to cool it down quicker.

New triple core rad and new water pump were installed, still overheats.

[tubz]

Originally Posted by bobss396

Was the manifold also changed, obviously it was off the car for the cam and lifter job. I can only think of a couple of things off hand.

Check the timing first, it should be fairly close to stock specs. Badly retarded timing will cause overheating. Another is when the manifold was put back on, did they block off any of the ports that run under the carb? Some intake gasket sets had these little metal plugs that would block them off and could cause overheating for the wrong application.

As a last resort, make sure your radiator hoses are not collapsing, have your radiator cap and cooling system pressure checked, make sure your fan belt is not slipping, did they reinstall your fan shroud?

It has to be something very basic, good luck.

Bob

Rad,hoses, belts, and water pump are all new. I wondered about the intake gasket, the mechanic that did the work says its OK, but I may have to take off the intake and check the gasket anyway.

[bobss396]

Just to get around with it, try removing the thermostat and see if it runs cooler. Test the thermostat while you're at it, drop it into a pot of boiling water and see if it opens up. Run the engine with the radiator cap off and see that you have full flow inside the radiator.

You have a very basic problem there, the trick is to out think it. Is there any chance of taking it back to the shop that installed the cam and other items? They should stand by their work, since it didn't overheat before they should at least take a good look at it for you.

Bob

[Rally Sport]

Yeah, maybe you have a problem with your thermostat.