Over heating issue

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Apr 2, 2010 | 02:53 PM

corvettedave383

Thread Starter

Burning Brakes

Joined: Apr 2008

Posts: 825

Likes: 40

From: Glasgow, Scotland

Over heating issue

I have a over heating issue at present, which has appeared over night, I have the dewitts rad, with twin electric fans, which seem fine, come on a correct time, and stays on trying to cool engine, but temp still raises, over 230+, heading for the red, just sitting on driveway idleing, the temp always went to about, 180/190, and stayed there, never went above that temp, fans would come on now and again to keep temp in check, so it seems all is working with that part of the system

The top rad hose is hot, but the bottom rad pipe going back to water pump, seems cool, luke water at most, is that correct, I would have thought that would be hot to?

Iam thinking maybe a issue with the water pump or water thermostat in the intake, whats peoples thoughts?, the waterpump is only a year old, not done very many miles on it, the thrermostat is maybe about 2 years old, engine is the same age, and same with rad and fans, 78 vette

cheers

dave

Apr 2, 2010 | 03:10 PM

Racer11

Racer

Joined: Nov 2006

Posts: 264

Likes: 0

From: McLouth Kansas

With a over night change,,I would wonder about the sending unit or gauge issue....Maybe install a temporary aftermarket gauge, the kind that requires no electrical hook up, just the probe that goes in the water port on the intake. And the thermostat could be the bad guy as well

Apr 2, 2010 | 05:09 PM

Rebelrob

Drifting

Joined: Jul 2009

Posts: 1,532

Likes: 14

From: Dallas-Fort Worth TX

Do you have a laser temp gun? I have heard many members troubleshoot with this by measuring the temp at the thermostat housing. Let us know what ya find out.
good luck.

Apr 2, 2010 | 05:36 PM

71coupe454

Burning Brakes

Joined: Jan 2009

Posts: 1,224

Likes: 1

From: Clarksville Indiana

T-stat stuck closed... if you take it out with the engine good and hot it should be wide open and then close as it cools. If you take it out cool, put it in a pan of water on the stove and see what temp it opens, if it does at all..

Apr 2, 2010 | 05:42 PM

Jeff_Keryk

Drifting

Joined: Feb 2005

Posts: 1,879

Likes: 38

From: Los Gatos CA

If the temp just keeps climbing, suspect coolant flow problems. Thermostat is an easy repair. If it gets hot around town (in traffic) suspect insufficient air flow across radiator. I like thermo clutches and AC type steel fans. At freeway speeds there is plenty of airflow, so suspect weak or undersized radiator. Of course this assumes a good pump, shroud, etc.

Apr 2, 2010 | 05:54 PM

Project80

Racer

Joined: Mar 2008

Posts: 428

Likes: 0

Quote:

Originally Posted by 71coupe454

Apr 2, 2010 | 07:09 PM

corvettedave383

Thread Starter

Burning Brakes

Joined: Apr 2008

Posts: 825

Likes: 40

From: Glasgow, Scotland

Thanks guys for info, when I was driving today, doing about 40 mph, the temp was still rising, still quite cool over here, it must be the thermostat, Ive got a temp gun, I will give that a try tomorrow

thanks

Apr 3, 2010 | 10:44 AM

corvettedave383

Thread Starter

Burning Brakes

Joined: Apr 2008

Posts: 825

Likes: 40

From: Glasgow, Scotland

Well done everyone who said it was the stat!, took it out this morning, run the car for a while , it wouldn't go above 160 f , idleing, drving it around the place, I checked the temp with my thermo gun thing, that agreed with the temp gauge, 160 f, the cooling system must be working quite well, it wont go above that temp, I need to purchase a new stat, which temp stat do peeps recommend?, 150, 180?? etc

cheers

dave

ps. weird how it has stoped working after such a short period of time!