Leak-down test on a 4.2?
06-11-2013, 11:20 AM
#1
Junior Member
Thread Starter
Join Date: Mar 2013
Location: Oregon
Posts: 3
Likes: 0
Received 0 Likes
on
0 Posts
Leak-down test on a 4.2?
So I bought myself a project truck- a 97 F-150 with a 4.2. The guy I bought it from said they found coolant in the oil so they assumed it was the head gasket and started to tare the engine down before giving up and buying a new truck. He got the valve covers and intake off before stopping.
After researching a lot I discovered the 4.2 is famous for leaking coolant into the oil though the intake manifold gasket and it doesn't have to be a head gasket leak, well sure enough I inspected the already removed intake gaskets and they were so bad they almost crumbled just by touching them and looked like they very likely were leaking.
I'm debating if I should just replace the intake gaskets and put it back together and hope for the best or put out the extra money and do the head gaskets anyway while I'm in there (I do not have a big budget set aside for this project so the less I spend the better). I have a leak-down tester, and that's where my question comes in.
When I hook it up to ANY of the cylinders, on either side, I get about a 20-25% leakage, The lifters are off the valves so TDC shouldn't be an issue, but it seems to be leaking into the "valley" under where the intake manifold would be but I can't pinpoint exectly where. I would think it was the head gasket, but what are the odds that all 6 cylinders would leak the same amount? Has anyone done this before on this engine? am I missing something?
Thanks for any help.
After researching a lot I discovered the 4.2 is famous for leaking coolant into the oil though the intake manifold gasket and it doesn't have to be a head gasket leak, well sure enough I inspected the already removed intake gaskets and they were so bad they almost crumbled just by touching them and looked like they very likely were leaking.
I'm debating if I should just replace the intake gaskets and put it back together and hope for the best or put out the extra money and do the head gaskets anyway while I'm in there (I do not have a big budget set aside for this project so the less I spend the better). I have a leak-down tester, and that's where my question comes in.
When I hook it up to ANY of the cylinders, on either side, I get about a 20-25% leakage, The lifters are off the valves so TDC shouldn't be an issue, but it seems to be leaking into the "valley" under where the intake manifold would be but I can't pinpoint exectly where. I would think it was the head gasket, but what are the odds that all 6 cylinders would leak the same amount? Has anyone done this before on this engine? am I missing something?
Thanks for any help.
