Engine Vacuum Caps

[BigBrother-84]

Hi Gentlemen!

Yesterday, finished installing a NOS speed control "Dealer Installed Kit".

Had to plug the system to an free engine vacuum port.  I took off one plug cap and discovered it was completely dry and cracked… although it looked good.

I share this in order to remind members that our trucks aren’t young and little things like that should be part of a regular renewal check list.

Easy to forget, but can interfere with engine performance.

[Gary Lewis]

Thanks, Jeff.  Glad you mentioned that.  

[mat in tn]

please save yourself some headache, and some whining from bystanders about your "old dated crap" and by a pkg of brite colorful vinyl vacuum caps and not the available rubber ones. I know the colored ones may not look original, but they are as close to "set and forget" as these get. the rubber ones will do this again and again. and to be fussing on the road over a vacuum cap is just not worth it.

[81-F150-Explorer]

I've been known to use a piece of Fuel Grade hose with a screw in it for a decent vacuum cap alternative.

The vacuum caps that are sold now days cannot handle the fuel vapor from the intake with the engine shut off.  It's like running windshield washer hose, for the PCV or the vent line from the fuel tank. The Fuel vapor will rot them.

[ArdWrknTrk]

One might consider the silicone caps often sold to protect hose barbs and screw threads from powder coat.
They are pretty inert and easily handle the oven heat.
IDK if an assortment is available in all black but I see a few sets on Amazon that are color coded by size (1/8-1/2")

[Gary Lewis]

That's a good idea, Jim.  I have a multi-colored set from Eastwood and they've held up well with powder coating so I'm sure they'd handle the underhood environment well.  

Caplugs appear to sell things for masking, and their HVC Series comes in a wide range of sizes.  They are vinyl but should stand the temp.  And they offer free samples, so maybe someone wants to test them?

[grumpin]

I tried hypalon caps, then sold the truck. They were holding up good.

Maybe if Bryson sees this he can comment.