Temprature of head covers comapred to internal Temprature
Discussion
I am checking out a problem on the engine of one of my old cars.
It could be a head gasket, but a lot of the issues don't make sense. They were replaced very recently and the heads skimmed.
The engine is an old large capacity V8.
I used an infra red thermometer to see if there were any hot spots on the engine and radiator.
When the internal temp gauge was at 70 c, the cam covers near the plugs were showing about 85-90c. I have previously used an external thermometer to check the water temp and found the internal gauge to be very accurate.
I then took the car out for a very hard run, using max revs a few times and a high speed cruise for 4-6 miles and then a shorter slower cruise. The cooling fans appeared to be on most of the time, although normally they wouldn't be on a motorway. The cooling of the car is crap due to design and airflow.
When I returned and checked the temp again, it appeared to be about 95-100c pointed at the same places
I have never used an infra red thermometer before to check engines, so was not too sure what temp to be expected on various parts of it.
Does anyone else have a view as to what external metal compared to internal water temps should be?
There were no obvious 'hot spots' or variations except the rear most cylinders were slightly cooler, as one may expect from water flow, going from back to front where the tank and rad were. There appeared to be no great variation from bank to bank.
I am trying to ID the overall problem of the engine appearing to be warm, and suspect a lazy water pump, but this temp issue perplexed me quite a bit, hence this post. I had expected the external temp to be about the same as the water temp, not so high!
Paul
It could be a head gasket, but a lot of the issues don't make sense. They were replaced very recently and the heads skimmed.
The engine is an old large capacity V8.
I used an infra red thermometer to see if there were any hot spots on the engine and radiator.
When the internal temp gauge was at 70 c, the cam covers near the plugs were showing about 85-90c. I have previously used an external thermometer to check the water temp and found the internal gauge to be very accurate.
I then took the car out for a very hard run, using max revs a few times and a high speed cruise for 4-6 miles and then a shorter slower cruise. The cooling fans appeared to be on most of the time, although normally they wouldn't be on a motorway. The cooling of the car is crap due to design and airflow.
When I returned and checked the temp again, it appeared to be about 95-100c pointed at the same places
I have never used an infra red thermometer before to check engines, so was not too sure what temp to be expected on various parts of it.
Does anyone else have a view as to what external metal compared to internal water temps should be?
There were no obvious 'hot spots' or variations except the rear most cylinders were slightly cooler, as one may expect from water flow, going from back to front where the tank and rad were. There appeared to be no great variation from bank to bank.
I am trying to ID the overall problem of the engine appearing to be warm, and suspect a lazy water pump, but this temp issue perplexed me quite a bit, hence this post. I had expected the external temp to be about the same as the water temp, not so high!
Paul
If you are expecting a coolant to cool lumps of metal then the metal is always going to be higher or there would be no thermal transfer.
Beware of relying on those gauges as you can get quite different reading depending on the surface. For instance they do not work well on shiny surfaces.
Steve
Beware of relying on those gauges as you can get quite different reading depending on the surface. For instance they do not work well on shiny surfaces.
Steve
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