Quick advice: Retorque or Replace Lower Intake Manifold Gasket

[lobo411]

Hi all,
I need some quick advice. 1996 Explorer XLT w/ 4.0 OHV 158k. I spent 1.5 hrs this AM tearing down the upper engine so I could retorque my lower intake manifold bolts. I've been seeing a small amount of something brownish/jellyish on my radiator cap and the radiator filler tube, which I think is oil. Also had an occasional ping on hills, and I haven't been able to get the engine above 190 under any conditions. Oil on the dipstick tube looks perfect, trans fluid dipstick tube looks great too. The car is running great otherwise--20 mpg, no codes.

I replaced the lower intake manifold gaskets when I replaced the head gaskets/did a valve job about 30000 miles/10 yrs ago.

I just checked the torque on the lower intake manifold. All the bolts on the Driver's Side were fine (144 in-lbs), and all the bolts on the passenger side were loose by about 1/2 turn.

Now my dilemma:

A. I found my problem--loose bolts. Retorque and sew her up. Leave well enough alone--don't go looking for trouble.

B. You've gone this far--just replace the lower intake manifold gasket. It's just 10 bolts + the valve covers.

Quick thoughts/advice? It's 9 AM here so I have all of today.

 

[koda2000]

i'd go ahead and replace the intake manifold gaskets. at this point re-torquing may help (i doubt it) but the fact that you found them to be loose may be indicative of the gasket failing. use good quality gaskets (like Felpro). see if Felpro offers a Perma-Dri gasket for your application. the Perma-Dri gaskets are the best available.

BTW, i don't see why this would have anything to do with your engine temp. how are you determining a max 190F degrees? if this was true you thermostat would not be opening. are you using a thermal temp sensor? if so what are you pointing it at? what is the ambient outside air temp?

 

[lobo411]

i'd go ahead and replace the intake manifold gaskets. at this point re-torquing may help (i doubt it) but the fact that you found them to be loose may be indicative of the gasket failing. use good quality gaskets (like Felpro). see if Felpro offers a Perma-Dri gasket for your application. the Perma-Dri gaskets are the best available.

BTW, i don't see why this would have anything to do with your engine temp. how are you determining a max 190F degrees? if this was true you thermostat would not be opening. are you using a thermal temp sensor? if so what are you pointing it at? what is the ambient outside air temp?

Thanks for the reply! I'm going to go ahead and replace the gasket. I guess getting 10 years out of it isn't bad, even if they only have 30k mi on them.

I killed time waiting for a reply by going to Autozone and getting some Fel-Pro permadry gaskets. Great deal too--I had a 20% off coupon so I got the whole kit for $77 w/ tax.

I was using the live data from my scanner to get the operating temperature, plus the gauge reading, which was dead-center between C and H for 10 years. I changed the T-stat in the summer and then it hung out in the lower 1/4-1/3, so I changed the T-stat again last night. But then I boiled the old T-stat with a candy thermometer and it opened up right at 198, so I guess that's not the problem. I'm not losing any coolant. Could just be a fluke I guess, but I'm going to order an infrared thermometer just to be sure.

 

[lobo411]

Great...now I'm in trouble. The vacuum line from the EGR to the fuel regulator broke in several places (I don't even know where the connector to the EGR went. Guess I should have just retorqued it.

 

[lobo411]

OK, I got another vacuum line segment from the junkyard, so I'm good there. I didn't want to have to piece together a vacuum circuit from the parts bin at autozone.

The gasket was leaking, but it probably had a fair amount of life left in it. The rubber was beginning to deteriorate, and the area that was weakest/possibly leaking was the area around the passenger side coolant passage.

I only got the lower manifold and the valve covers reinstalled by the time it got too dark to work. I didn't replace the fuel injector rail gaskets because I don't have the reverse torx bit. Haven't decided yet whether I'll do it tomorrow or leave well enough alone!

 

[lobo411]

Why do they give you two fuel rail gaskets? I replaced the upper intake manifold gaskets a while ago and that set came with two fuel rail gaskets (I didn't change the fuel rail gasket though). The complete intake manifold set I bought also came with two fuel rail gaskets. Are you supposed to use both in the sandwich between the fuel rail and the lower intake manifold? Or is it just extra--they give you 6 upper intake manifold O-ring gaskets too and it only requires 3.

Or based on the Ford diagram, did they use two fuel rail gaskets from 1990-1994 and not on 1995+? The diagram shows a gasket between the fuel rail and the upper intake, but it says "1990/94"

 

[lobo411]

It looks to me like the new fuel rail manifold gaskets won't work. The original gasket was a sandwich of a paper gasket, a 1/8" plastic shim, and another paper gasket.

The new Fel-Pro gasket kit I bought (and every single other gasket kit I can find on the internet) is just a paper gasket.

I tried reassembling my fuel rail with just the new paper gasket, and it wouldn't work. There is a 1/8" gap between the fuel rail and the lower intake manifold. It seems that the shim is required on this engine. I guess I'll just reassemble using the old gasket, but it's really disappointing that there's no workable gaskets or even any info out there on this issue.

 

[lobo411]

OK, the car's back together, but I broke the vacuum line section from the EGR solenoid or whatever so I have to go back to the junkyard tomorrow and get that.

Had a minor heart attack when I fired it up and it started idling poorly. I figured it was miswired (idiotic Ford firing order), but I actually wired it correctly this time. I fired it up again, and got a CEL for P0353 -- coil #3 not working. So I unplugged the spark plug wire at the coil and plugged it back in, worked the spark plug wire at the plug a little to make sure I had a good connection, and unplugged/replugged the fuel injector connector. I didn't notice anything unusual, but it fired up and idled fine.

 

[Dono]

excellent, Im sure this will fix your pinging issue.
With age, things seem to get a bit brittle, and easy to break. You sure moved quick on the repair.

 

[lobo411]

excellent, Im sure this will fix your pinging issue.
With age, things seem to get a bit brittle, and easy to break. You sure moved quick on the repair.

Thanks! Ya, the downside of having an old car is that everything breaks with the slightest gust of wind. The upside is that I've taken everything apart before all the way down to the head gaskets, so I have my bag of tricks!

I sure hope so...I'll take a picture of the old lower gasket and the old new plugs. The plugs look normalish, but I expected them to be a bit cleaner since they only have about 4000 miles on them. They were single platinum Autolite AP605's, and I switched to double platinum APP605s.

Drove the car to the gym today and it seems to be better. I have plain water in the radiator now because I need to do a flush, so that may be the reason, but the ECT seems to be getting more into the "normal" temp range.

I didn't try to test for pinging yet, because I need a good steep hill/mountain. I didn't think it was wise to floor it before I had the cooling system back in proper order (finish the flush first).

 

[Dono]

careful with the plain water. Things rusted up in a real hurry when I did that.