Thread: Defender Engine Bay Heat - LH guard vent

Those bonnet side vents are on a mates county, i didnt put them on mine as i figure any hot air coming out would go in my windscreen flap vents[mates county doesnt have the opening vents[yet]]

Originally Posted by MacFamily

While looking for defender related stuff on google last night, I came across this web site, Iam not sure how effective these bonnet vents are, but would have to remove sum of the hot air.

Defender 110 1993

They're in totally the wrong spot/s to vent radiator air.

I've written this quite a few times now.

Ideally vents need to be in an area of laminar flow or an area of low pressure.
Back near the base of the windscreen is a high pressure zone so if using the top of the bonnet they need to be further forward, ideally not too far behind the radiator.

For inspiration look at where cars that spent time in the windtunnel have their bonnet vents, think Mitsubshi Evo's, etc.

I wouldn't put them there on a pre-TDci Deefer for the reasons redrovertdi stated.

However, when my old V8 rangie had overheating problems was only during low speed off road. Then it would probably have benefited from holes anywhere to let hot air out and there would not have been high pressure at the base of the windscreen.

Originally Posted by Bush65

However, when my old V8 rangie had overheating problems was only during low speed off road. Then it would probably have benefited from holes anywhere to let hot air out and there would not have been high pressure at the base of the windscreen.

My 83 range rover had the same symptoms, cure was a later model 4 core radiator and electronic ignition, remember the v8 doesnt have a 700degree turbo in the engine bay.
Richard

Originally Posted by Bush65

However, when my old V8 rangie had overheating problems was only during low speed off road. Then it would probably have benefited from holes anywhere to let hot air out and there would not have been high pressure at the base of the windscreen.

Just remove the bonnet, problem solved

A decent fan could help too

Luckily you only have oil burners to not worry about these days

Originally Posted by redrovertdi

...., remember the v8 doesnt have a 700degree turbo in the engine bay.
Richard

My V8 Landys were always hotter under the bonnet than my chipped & boosted Td5 is,

I never get that open the bonnet and a heatwave hit you in the face like opening an oven with any of my turbo diesels like I did with my 4.4 or 5.0 V8 Landys

Thanks for the useful info rick130, uninformed and rainmain. Running cooler now with the vent done 👌

Looks good wazza! I have just marked mine out, will be cutting both sides tomorrow and I have some black mesh lined up.