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Removal of lower rad intake

Posted: 12 Jan 2006, 14:19
by kevtherev
I have a 1.9 water cooled '86
Now I like the look of the A/C front ie without the lower grill, I think it looks more natural to the van..
Has anyone covered it up and overcome the subsequent cooling problem' or even removed it completely.

My own idea was to trunkate the airflow from under the bumper,
or install some extra fans on the bottom of the rad

any ideas?

Posted: 12 Jan 2006, 14:31
by Diamond Hell
It's there for a reason.

Talk to Martin M3MJE about having the lower air intake blocked off - he runs a 1.8 I4 engine in what was an Aircooled van.

Posted: 12 Jan 2006, 22:48
by Aidan
There was a 1.9 w/c van on ebay last year - that had had the lower panel replaced with the a/c one and a few holes drilled into it in lieu of the big gaping hole and grill- it always ran hot - like 2/3, just below warning light coming on point. The guy who was selling it didn't know it was the wrong panel - it was like that when he bought it, but he was selling it on again. That's got to be the quickest way to shorten the life of an engine apart from not checking the oil level.

Posted: 13 Jan 2006, 00:18
by Blingpanzer
Typical manufacturer's cooling trial: load van to its Gross Vehicle Weight, couple-up a towed dynamometer and then drive, slowly turning up the setting on the dyno until the van is running at maximum torque (and hence maximum heat transfer to the coolant), usually at about 25-30mph depending on which gear is being evaluated. At this point, the heat developed and exchanged with the air is huge, and can be witnessed as waves of heat circulating all around the radiator grilles and engine bay. To cool the van down afterwards you must leave the engine running at idle so the coolant can still circulate; if you keyed-off, the afterboil would finish the engine in short order. The radiator is made the size that it is for a reason; any bigger would be unnecessary expense, any smaller would provide insufficient heat exchange (obvious really...).

The cheapest way for VW to productionise the vans with watercooled engines would have been to keep the Aircooled-spec lower panel. Instead, they tooled-up for a new lower panel and engineered an extra grille and its fixings (new press/mould tools and increased parts count: not cheap, and not done lightly). The extra cooling area is there for a reason. The upper grille only provides airflow/exit for about 30% of the surface area of the radiator - delete the lower grille and there'd be 70% of the radiator unable to function properly, apart from some ram-air effect from below the bumper (less if you have an underbumper spoiler fitted).

The worst condition is hillclimbing in 2nd/3rd with a load on (e.g. a camper conversion); slow speed = very little ram-air effect, engine working hard at or near maximum torque and hence maximum heat generation, hence the cooling system needs as much open area to exchange heat with the ambient air as possible to avoid overheating.

Still want to delete that grille?

Posted: 13 Jan 2006, 13:47
by crazydiamond
Just paint the lower grill to match the body colour, it wont be so noticeable then!