Author Topic: Rad cap  (Read 6980 times)

Offline Ill Named

  • Newbie
  • Posts: 17
Re: Rad cap
« Reply #15 on: October 06, 2008, 09:07:01 pm »
I may have found the culprit. Tonight I put a coolant system pressure tester on it. I pumped it up to about 14#'s and watched it. The needle barely moved in about three minutes, but it did move (I'm talkin about a thirty second of an inch here, maybe less) So then I released the pressure, started the truck and watched the gauge. It climbed slowly like it should, but then at about eight pounds or so the needle started to vibrate, not very much, but it did vibrate a little. That is enough to make me think that I have a head gasket issue (aluminum heads) I decked the block, Have brand new heads, and used felpro marine gaskets, which I was told were the best, and I still have a head gasket issue. I am going to buy a compression tester tomorrow and check it over, if I do have a by-passing issue it should show up on the compression gauge shouldn't it?

Something still just don't jive here for me though. I checked my new 13# cap and it is working fine. I never loose coolant, which you'd think I would, cause I would assume that coolant would be getting sucked into the combustion chamber and ran through the exhaust. And I would also think that with all the excessive pressure being built up, the rad cap would be open constantly over flowing  my over flow tank, which doesn't happen. Maybe I should just try a hose reducer adapter like vile suggested. What do you guys think. I am almost at my wits end here.
Ill
« Last Edit: October 06, 2008, 09:33:25 pm by VileZambonie »

Offline VileZambonie

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 19171
Re: Rad cap
« Reply #16 on: October 06, 2008, 09:35:19 pm »
Put a spill free funnel on the radiator and check for hydrocarbons with a gas analyzer at the funnel. Any garage can do this for you. If you have HC's present you are leaking combustion into the cooling system.
,                           ___ 
                         /  _ _ _\_
              ⌠ŻŻŻŻŻ'   [☼===☼]
              `()_);-;()_)--o--)_)

74 GMC, 75 K5, 84 GMC, 85 K20, 86 k20, 79 K10