Overheating problem with the Caddy

Slick 50 · March 15, 2004, 06:15:18 PM

When I'm driving around 60 or so mph the temp indicator reads at roughly the 3/4 mark, but when I slow to 55 or slower or idle it reads "normal" or about mid point on the guage.

I just read in the manual that there's a plastic impeller in the waterpump and I'm thinking the impeller is worn and that it's not flowing enough coolant at the higher RPMs.

Or it could be a faulty thermostat. But what are the chances of the problem being the least expensive and easy to fix part?

Any ideas or suggestions?

parklane · March 15, 2004, 08:48:15 PM

Ken
You have two chances of it being the cheaper repair - slim, and none.

John

Bruce Dorsi · March 15, 2004, 10:13:50 PM

I don't know the history of your Caddy, but could you have a partially clogged radiator?

Radiator hose collapsing on suction side of pump?

Is your fan a direct drive, or a thermostatic clutched-drive?

Slick 50 · March 15, 2004, 10:45:34 PM

Quote from: "Bruce Dorsi"I don't know the history of your Caddy, but could you have a partially clogged radiator?

Radiator hose collapsing on suction side of pump?

Is your fan a direct drive, or a thermostatic clutched-drive?

The radiator was cooked and flushed a short while ago (early last summer).
The hoses are in good shape, but I'll check them. And it's a direct drive fan with a stock shroud.

SKR8PN · March 16, 2004, 06:13:39 AM

It has been on RARE occasions that I have found a slipping impeller on a water pump.It does happen,but not very often.From what you have described, I would take the radiator out and have it flow checked before I did any other repairs. Just my $.02

HOTRODSRJ · March 16, 2004, 06:34:34 AM

Ken.......flow certainly could be a problem but your radiator is supposed to be expotentially more efficient at higher speeds. Notwithstanding the impeller issue (if it really is?), my guess would be a too lean condition which is the most common cause of increase in temperature at speed.

Have you a new carb or rejetted lately. What has changed? How about an intake leak? Overly lean conditions will make heat FASTER than most radiators can handle.. I would jet fatter to see what happens.

Also on the "suction" side of the pump, even a new hose can collapse at speed. Do you have a spring inside that hose? I have seen this restrict flow too as the boys here have pointed out.

Also, a minor point but where is the sensor? Is it a head sensor and is it near a header that could be tainting the reading?

Slick 50 · March 16, 2004, 07:59:04 AM

Quote from: "HOTRODSRJ"Have you a new carb or rejetted lately. What has changed? How about an intake leak?
Do you have a spring inside that hose?
....where is the sensor?

No carb changes. There is no spring in the suction hose. I'll check that hose out as well as vacuum leaks. The sensor hasn't been touched from the factory spot but I'll look at that as well.

Thanks for the ideas guys!

OFOF · March 17, 2004, 05:35:53 PM

Just a thought, but, if it doesn't puke water/antifreeze on a hot day leave it alone. It could be a sending unit/guage problem. A lot of folks spend a lot of money on cooling problems where there really is no problem. If it is really too hot it will overflow. Then you know you have a problem.
Good luck! Don.

Broman · March 20, 2004, 01:03:55 AM

I have a similar problem with my Buick. Well I think so anyway. I think I have aready replaced everything but the waterpump and the radiator, and it looks like the waterpump is where the problem is. It doesn't act like a bad wp, but that's the most logical solution I could find.

Anyone have a good cheap place to get a waterpump for a '50 Buick I8? I bought one from my local parts store without even thinking about the two different engine sizes - only to find out that the one I got was the wrong one. Figures. Then I go back toget the right one and they only carry the one I ordered...mthrfckinsmbtchncoksukers...

The WRONG one was 90 bucks!!!

I hope the right one is cheaper...