can we run engine without the top cover ?

[numberplate]

hi guys / girls

just a thought - is there any disadvantage to running the engine with the top insulation cover removed ? I'm not sure if its part of the designed airflow / cooling system.

i have a theory that the upper cover tends to hold heat in the engine , so removing it may improve airflow at the expense of some extra noise.

any other thoughts ?

[TOYZX]

Ever heard an early prado vs am early hilux? Main difference was that cover which the prado has always had, makes a massive difference in engine noise! There was a couple of guys who managed to fit them to their lux just to shut them up!

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[MikeO]

My 2009 2.5 D4D never came with a top cover and it isn't too noisy. Don't know how this might effect an 3 L D4D.

[hiluxxury]

The cover on top of the intercooler? I've been running without one for a few years now. I forgot to put it on after working on it once a long time ago.

I had the same theory about holding heat around the intercooler... but I never tested it. I think it was Boxhead a while ago who noted that bullbars with high top bars can deflect airflow away from the bonnet scoop affecting intake temps but a couple of degrees - so the intake temp system is sensitive to changes in airflow.

I cant remember if it makes any difference to noise levels (I think the prado tappet/head cover does make a difference).

[fracturedranga]

I havent got one on mine as im running a front mount intercooler its not noticably louder and didnt make any difference to coolant or oil temps