Originally Posted by Jeff9
I picked up a set of Lebaron hood vents for $4 yesterday from a JY. I'm debating putting them in.
I've seen many threads detailing installations of hood vents, but none that discuss whether or not they have any real effect on cooling. What have your results been?
Also, for what it's worth, I don't have a cooling problem.
Originally Posted by Jeff9
I've seen that link before. I'm talking about coolant temps and effectiveness when idling or moving slow.
This fella has done all the hard work with proper results regarding temps and fitting location. ...
Yessss .... its a TJ
.... but its applicable to just about anything.
If however ... your XJ spends all its time in low range or at low speeds .... hack some holes anywhere you want ... as - if your fans are working properly - hot air will be blown out .... and as physics dictates ... hot air will rise out when the engines switched off.
If you spend time at highway speeds ... then the fitting location becomes a bit more critical for effective
Best locations for "vents" are in the rear, corner areas of the hood ... or even high up at the rear of the fender.
A 40series landcruiser or a jeep KK are probably, relevant examples ... unless you prefer the look of the euro XJ orvis models with fake vents ...
Easiest location to fit "vents" is the flat, unsupported areas of the hood ..
Since the XJ hood basically sits on the valve cover ... its also presumed that, thats the "hottest" spot - needing attacking with a bucktooth squirrel or a sawzall ..
I run spacers in the hood hinges since its easy. Also have a larger firewall seal to plug the gap between the hinges to stop unwanted
Did it lower underhood temps ?? ... marginally - but that wasnt the result wanted ... The goal was providing some additional
underhood air movement at all
vehicle speeds ... as moving air is cooling air - and static air, is insulative.
Coolant temp changes were also marginal as one would expect ... but the additional venting action does help stabilse the coolant temp somewhat ... in conjunction
with a few other cooling system tweaks.
As mentioned above ... do some testing at various vehicle speeds and driving tasks.
Space up the hood hinges,
Space up the hood hinges with a larger firewall seal between the hinges,
Tape on some tell tails, especially under the hood along the rear, from corner to corner,
Do some temp tests if you can.
Dont forget the fanclutch needs certain engine bay temps to operate correctly ... and dont confuse any new underhood temps over 20mph ... with the temperature of the air being jammed in from the windscreen, disrupting the radiator air intake ..
When you think you have vehicle airflow all figgered out according to what you have been seeing .... bang in some holes and louvered thingos to duplicate the best result ... as close as possible.