[Healeys] Overheating

Sat Mar 6 17:49:44 MST 2021

Using an original type stat helps too ie the one with a sleeve. Helps, not cures all.

Simon

From: Healeys <healeys-bounces at autox.team.net> On Behalf Of warthodson--- via Healeys
Sent: 06 March 2021 23:41
To: rfbegani at gmail.com; michaelsalter at gmail.com; bspidell at comcast.net; healeys at autox.team.net
Subject: Re: [Healeys] Overheating

It seems to me that switching from a 7 PSI radiator cap to a 15PSI cap is not a solution to an overheating problem but rather a band-aid.   
Gary Hodson

-----Original Message-----
From: rfbegani at gmail.com <mailto:rfbegani at gmail.com> 
To: 'Michael Salter' <michaelsalter at gmail.com <mailto:michaelsalter at gmail.com> >; 'Bob Spidell' <bspidell at comcast.net <mailto:bspidell at comcast.net> >; 'Ahealey help' <healeys at autox.team.net <mailto:healeys at autox.team.net> >
Sent: Sat, Mar 6, 2021 3:58 pm
Subject: [Healeys] Overheating

Bob & Mike:

You both may have seen my requests on overheating of my BJ8 and the response from the group.  As a result, I purchased an infrared thermometer to determine if my water gauge was giving accurate readings.  The thermometer gun told me that my water gauge was 30 degrees higher than the temperature of the sensor attached to the block.  At the same time, I noticed my gauge will show 120 degrees at rest instead of going down to 90 degrees which would indicate a 30-degree high reading.  In May when I leave for cool Michigan, I will send the gauge to Nisonger to be rebuilt.

I began to test the temperature of the water going through the cooling system at the inlet to and outlet from the block, inlet and outlet to the radiator and the upper and lower hoses while the engine is running at idle and at 2-3 Thousand rpm.  The chart I created to record these temperatures allowed me to produce observations or averages because the flow of the water is dependent upon the rpms of the engine.  The engine has overheated all of the 40 years I have owned it and has only 1000 miles on the new speedo since rebuilding to 20 over. 

At the radiator inlet 134 outlet 85 at high rpms with electric fan operating.

                        inlet 103 outlet 94 at idle rpms with electric fan operating. 

The above temperatures are recorded at the inlet and all along the hoses.

These temperatures indicate the pump is circulating water with sufficient gallons to cool the engine only when the engine is at high rpms.  At idle the pump does not circulate sufficient water to keep the engine cool.  This is especially true when you have been operating the engine at high speed and come down to 30 – 40 mph and stop and go traffic.  Maybe the real answer is to install an electric pump for constant cooling water?

In the past week, I have installed a large Dorman coolant recovery tank and a new 7 psi 1 inch radiator cap because I learned that our radiators have a long neck.  Both those changes have reduced my problem of very high overheating and resulting boiling over.  In addition, when my water gauge shows 212 degrees the water temperature is actually 30 degrees less or approximately 185 degrees.  Also, I am not boiling over and loosing coolant.  Nevertheless, the engine water temperature is still spiking to 210 plus degrees true when coming off highway speeds.  

In my review of various sites, the radiator equipment suppliers and others are recommending increasing the pressure in the classic car systems to 15 psi plus, and coolant recovery tanks “if your coolant system, radiator, hoses etc. is new” and therefore can hold the pressure.  Unfortunately, I have not found any maker of a 1 inch depth x 2.33 inch diameter radiator cap except our 7 psi cap so I can try such a pressurized system.

Another suggestion on an older discussion at the British Car Forum indicated some of the Ontario car owners had switched to Evans Waterless Coolant rather than 50/50 coolant water mixture.

I still have no idea why a minority of our group has overheating problems.  More ideas?

Regards,

Bob Begani 67 BJ8 

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