Thread: Defender Engine Bay Heat - LH guard vent

Originally Posted by DiscoMick

Why not just put a snow cowl on the fake vent on the top of the mudguard and let the hot air vent out there?
Get one of these for the other side?

Because the air doesn’t draw out from there...

I am going to do something similar soon. I am going to use the same as the wing top vent and keep a blank in the car if I need to do a river crossing.

What point is the blank

Originally Posted by Tombie

What point is the blank

If I need to do a water crossing the vent can be blanked in a couple of minutes, will be looking at putting a vent in the guard lower outside panel, so the need for the blank.
Have the vent and ducted intake for the heater / fan intake and a blank on the other side as have relays in that spot.

Originally Posted by CraigE

If I need to do a water crossing the vent can be blanked in a couple of minutes, will be looking at putting a vent in the guard lower outside panel, so the need for the blank.
Have the vent and ducted intake for the heater / fan intake and a blank on the other side as have relays in that spot.

But if you blank it for a water crossing how does the water get out?

The vent on top of the guard is an intake for cabin fresh air.

I did this to my guard P1011307.jpg

Having this vent has not changed anything during water crossings.

Originally Posted by Colin

But if you blank it for a water crossing how does the water get out?

Same as it does now without one. The plan is to have a blank to stop water ingress into the engine area, obviously would be a wading sheet across the grill as well. I am putting the vent in to allow some of the hot air that builds up around the turbo and exhaust to escape.

I used an air intake vent in reverse to make my vent.
I was going to use a LHS guard vent to keep the lines vertical and horizontal, but my supplier was out of stock, so I used the RHS vent, I kept the horizontal line in line with the side indicator / curve ad the slanted look doesn't look too bad.
By having a rear facing vent I theoretically create a low pressure behind it and that helps suck hot air out. I can't test that theory though.
The other aspect I like is that for deep water crossing I can block the hole with some duct tape and maintain my high pressure air bubble against the firewall.

It drops heat build up against the firewall and improves airflow through the radiator and intercooler. On the 300Tdi I think it would work better than on a PUMA as it can wash out exhaust heat by being on the exhaust/turbo side of the engine bay.

I found on a 30.C+ day @ 100kph it drops EGTs by about 50.C