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'88 2.3 Compression Test Results


SenorNoob

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1988
Make / Model
Ford
Engine Type
4.0 V6
Engine Size
4.0
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Manual
2WD / 4WD
4WD
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1.5" Front + 4" Rear
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Cylinder 1.......................... 135
Cylinder 2.......................... 135
Cylinder 3.......................... 80 (115 after some oil in the cylinder)
Cylinder 3.......................... 140

This was done with the engine completely cold.

I've also noticed a significant amount of air bubbles at the radiator when the truck is running and the heater core keeps breaking loose. Sounds like compression leaking into a cooling jacket to me.

Just wanted to get some thoughts from the experts. Is a head gasket likely to do any good? Or is the whole thing weak enough that it wouldn't be worth it? Junkyard engine maybe? Although I've noticed an '02 FX4 on Craigslist not far from here. Only listed at $3500. (Too much for me but supposedly a good deal) Link for anyone else interested: http://clarksville.craigslist.org/cto/3412382313.html

A little background: I've been fighting this things low power since I got it. I had an '86 4x4 before so I know about where it should be. (It's fairly close.) I reworked the entire set of fuel lines (main pressure line was almost in two at the tank), changed the front fuel pump from one of those aftermarket universal deals to the correct one from the junkyard, replaced spark plugs, and the fuel pressure regulator to get it to idle correctly. Now this...

Thanks for any ideas you can offer.
 
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Rock Auto 5% Discount Code: F9A1A579ACFAD1: October 1st, 2021

Mark_88

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I would say at this point you are going to have to pull the head...if you don't see significant damage on the gasket then it is most likely a cracked head...

Since you are going to pull the head it might be a good idea to have what you need before you start...like a new head gasket and assorted other gaskets (valve cover, TB, intake, exhaust et al)...and you might want to, if this is your DD, go for the worst case scenario and have another head ready to go when you tackle the matter...

Squirting oil in and having the compression come up could indicate a few things though...like it's actually the rings or valves...so a leak-down test might be in order before you jump the gun here...if it's rings then, of course, the bottom end needs rebuild/replacement...if it's the valves then you're ahead of the game with a new head...so to speak...
 

SenorNoob

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Ford
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Engine Size
4.0
Transmission
Manual
2WD / 4WD
4WD
Total Lift
1.5" Front + 4" Rear
Tire Size
245-70-R16
Thanks.

I'm trying to prepare for any possibility when I take it apart so.. Couple more questions.

1) Would the later 8-plug heads work on this engine? I read somewhere the intake manifold shape is different but could the lower intake be used with my upper to make it work?

2) Are any of the heads "better" in any way? Different size valve or combustion chamber? Why not try for a hair more power while it's apart:D

OK 3 Questions: Can the factory header from the newer trucks be used? Just for looks under the hood. Will it bolt to the rest of the system?

Sorry if any of this has been covered before... (If so please point me that direction I'm just trying to get everything lined up for when I get a chance to work on it.

Thanks again.
 

4b316

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You can use up to a 94 head after that they are different.It sounds like from the way you described it,you have a crack between the valves on number 3 cyl.Hopefully it is just a broke head gasket in that location
 


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