Electric radiatore cooling fans - why?

Hi Guys, The OEM fitted feathering propellers to their engines and mine always did the job of cooling under all circumstances.

Post my NAT conversion and the 100% increase in BHP i have had issues with "heat soak" after a fast run. Is this why some members have fitted over run fan units to avoid heat damage to many items and most of all the cylinder head gasket.? Herbie.

I've never had any issues with mine after going NA-T. Cooling is one of the major improvements Toyota made with the MK4 as the MK3's go through headgaskets for fun.

What gives you the impression you're suffering from heat soak? Maybe it's just the exhaust side of the engine producing a lot more heat?

Hi Style, Thank you for the reply i heard before that the gaskets were not that good on the mk4's,this probably why some have fitted the "Cometic" gaskets which are much stronger, especially if the head has to be skimmed.

With reference to the "heat soak" i have had to baffle the down pipe to protect the brake master cylinder and the bulk head insulation, i also have gone through 3 new batteries in 2 years, and the starter relay, the ambient under the bonnet after a fast run is much higher than the pre NAT stock was. The batteries take time to fail and the starter relay is heat sensitive with a built in temp cut out.

I agree with you re the head gasket as the RPM, the compression etc are as pre NAT. I also agree with you about the most of the extra heat is the manifolds and the exhaust system. Herbie.

Never had any heat issues with my radiator. It's looking visually tired so I'm replacing it anyway.

I'd be looking at my exhaust gas temperatures to see if the engine is running too hot. This could also be a cause.

Hi Style, Thank you for the reply i heard before that the gaskets were not that good on the mk4's,this probably why some have fitted the "Cometic" gaskets which are much stronger, especially if the head has to be skimmed.

With reference to the "heat soak" i have had to baffle the down pipe to protect the brake master cylinder and the bulk head insulation, i also have gone through 3 new batteries in 2 years, and the starter relay, the ambient under the bonnet after a fast run is much higher than the pre NAT stock was. The batteries take time to fail and the starter relay is heat sensitive with a built in temp cut out.

I agree with you re the head gasket as the RPM, the compression etc are as pre NAT. I also agree with you about the most of the extra heat is the manifolds and the exhaust system. Herbie.

Yeah, it just sounds like there's a lot more heat being generated mate. 3 batteries in 2 years doesn't sound ideal though and wouldn't have thought it would be related to heat. Is there maybe something that's draining it like an alarm or something?

Do a current check when the cars all turned off and not running. Good idea Style!

If you have the stock fan, you NEED a fan shroud, that is the key to fan efficiency. People fit electric fans for a variety of reasons, extra cooling, gain a bit of power from removing the drag of the fan

Thanks for comments guys, pre NAT the batteries were Bosch as are the last three, i did a drain down test when the first battery failed, just the 'Tracker' and Cat.1.immobiliser as was the case for the past 10 years, so all ok. I went on a battery technical site and looked at a graph showing ambient temp against life expectancy it was quite revealing, it showed 70% reduction in life expectancy if the ambient went only 20% over their specifications.

This is why i fitted a louvre directly above the battery and another the same for aesthetic reasons above the turbo conical air intake filter, it looks good and the heat emittance when you turn off the engine is mega. On a hot summers day with a black car the heat ambient under my hood was 52deg.C. I never measured this pre NAT but i would bet it was much less. I firmly believe that 'heat soak' can and does cause fatigue to items under the hood at these temperatures, it takes time, but failure will come with time, IMHO. Herbie.

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