Intake manifold keeps leaking

[adrock430]

Hi all,
Been a long time reader here, first time poster (I think). I have a 94 ford ranger xlt w/ 4.0L v6. I've changed the intake manifold gasket three times now and the leak does not stay away.

It leaks from the rear closest to the firewall where one would apply sealant. There is some minor pitting in that area, but nothing too bad. I've paid special attention to this area when it comes to sealant application, but to no avail. Do intakes warp typically? Any tricks I'm missing here?
Thanks, Adam

 

[arco777]

If you have the aluminum upper manifold, no, I haven't heard of that being a common issue. I would suggest pulling the upper intake manifold off and checking the flatness of the mounting surface and that of the fuel rail. The fuel rail is removable by unscrewing the studs sticking up. Check that the fuel rail has a flat mounting surface on both sides and that it has a good gasket between it and the lower intake manifold.

If warpage is suspected you should be able to have a machine shop mill the items flat, or at least use a piece of straight bar stock with sandpaper to flatten the surfaces as best you can.

 

[jd4242]

Glob it with rtv and make sure to check the bolts a couple days later.

 

[arco777]

Glob it with rtv and make sure to check the bolts a couple days later.

Seriously? Fix it right, fix it once... Ford didn't spec RTV globs from the factory.

 

[jd4242]

Seriously? Fix it right, fix it once... Ford didn't spec RTV globs from the factory.

Umm yes they did, in all four corners where the LIM, head and block meet.....

 

[jd4242]

Seriously? Fix it right, fix it once... Ford didn't spec RTV globs from the factory.

It also states that the LIM show be tq down in sequence with the heads at the same time to properly align it...

 

[arco777]

Umm yes they did, in all four corners where the LIM, head and block meet.....

My apologies, I did not consider the OP might have been having issues with the lower manifold, figured it was the upper.

 

[jd4242]

My apologies, I did not consider the OP might have been having issues with the lower manifold, figured it was the upper.

Its all good.your suggestion is absolutely what should be done first and the proper way to test and make sure there isn't real problems. Mine was just the shad tree fix but should be used also once everything is proper.

Biggest thing is tho most people don't use enough rtv and don't check the bolts after a few miles.they have updated the gasket now but I don't like it.

 

[adrock430]

Thanks for the input guys, I've done all those things in the past: clean surface, laid down plenty of proper grade sealant, let it tack up, bolted in sequence, tightened again later. I'm thinking that I have to properly diagnose first (duh), maybe that I'm missing another source of leak in the rear of the engine. Dye and black light should let me know, right? Any other tips for ID or other possible/common culprits? Thanks! Adam

 

[arco777]

Is it leaking air or oil? If oil, see this thread - http://www.explorerforum.com/forums/showthread.php?t=389033

 

[adrock430]

Leaking oil, checked there, no oil. have some sludge in the rear of the intake, but I don't know if its from old leaks. Cleaned the tranny area on Saturday, haven't driven since...no further oil buildup

 

[malohnes]

I have similar troubles, but it seems my LIM bolts are the ones that get loose and then the oil leaks and I get death rattle along with leaking.

 

[adrock430]

Taking a hard look at the source of the leaks, my oil pan is leaking for sure, and I found a picture on this forum similar to the leak I'm experience.

http://www.explorerforum.com/forums/showthread.php?t=278434

Is this a rear main seal leak?

 

[tombstone]

Have a 94 Ford Explorer 4.0l (pushrod) and the trouble that I'm experiencing is that the engine ran smooth prior to removing upper and lower intakes(front manifold coolant leak). I replaced the one-piece lower gasket (FelPro) with a one-piece OEM F5TZ-9439-A (first version),plus everything was cleaned properly and Permatex Ultra-Black RTV was used around water jackets (front/rear) and joints wear block and heads meet , both sides of "new"gasket. Upon start up, engine ran rough and after warm-up there was still no improvement, so I tested radiator for presence of exhaust gas in radiator (block tester) 4-times and test fluid never changed color;which would indicate cracked head or bad head gasket ? Do you think that I should try the OEM F7TZ-9439-AA (updated version )1997-2000 ? I work on all types of cars without problems and this ones got me thinking ??? P.S. : No CEL , fuel pressure , coil , sparkplugs ,plug wires ,EGR solenoid, replaced ...