Interestingly enough, BOTH head gaskets on my 95RRC 4.2 L are leaking at the corners. Appears to be an external leak only - plugs look good, compression in all cylinders is around 130, etc. From what I have read, people say that head gaskets fail for a reason and you need to find the reason (i.e. warped decking, warped head, slipped liner, cracked liner, etc). My vehicle does not overheat at all so the thought of a slipped/cracked liner seems low probability. Who has replaced head gaskets on their 4.2? What did you find? Did you just replace the head gaskets? Did a problem re-surface? What else should I replace while I am in there? i.e. new lifters if lifters are cupped, etc??
This is my 1st post on this forum, appreciate the help!
Did mine last summer. I had the same symptoms, leaking antifreeze at the corners. Truck was running fine otherwise. I ended up removing both sides and having the heads cleaned and valve seals replaced. There were no signs of burning coolant. Heads didnt need to be decked and the block surface was perfect.
Just make sure you use composite gaskets and new head bolts.
Ok thanks.
My truck has had a rough idle/miss type thing for a while. Hold you foot on the gas and you feel it up until 2000 RPMs or so, then you can't feel it. Also has loss of power (could just be getting old). What does this tell you if anything??
^^^^ x2
WE did ours last April.
The new gasket will eliminate some bolts on each side that were useless. They actually caused the head to be torqued too much on the low side.
You can do it right in the engine bay. And that's what I suggest. We swapped motors to do mine and it was a nightmare to put back in.
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Originally Posted by msggunny
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2003 Discovery II SE, 1993 Range Rover LWB
Ok thanks.
My truck has had a rough idle/miss type thing for a while. Hold you foot on the gas and you feel it up until 2000 RPMs or so, then you can't feel it. Also has loss of power (could just be getting old). What does this tell you if anything??
Clean the Air Idler Valve and check your vacuum hoses.
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Quote:
Originally Posted by msggunny
I punch my clown daily.
Where are you? Get on the map.
2003 Discovery II SE, 1993 Range Rover LWB
all the other stuff for poor idle etc has been looked at (stepper, vacuum hoses, cap, wires, YOU NAME IT!). So I was wondering if head gaskets relate to any of these symptoms that's all...
Do a compression test before you dive into head gaskets.
Also check out your fuel system. My 95 RRC had severe rust inside the fuel rail. Truck sat behind a dealership lot for a year before I bought it. There was so much rust in the rails that it could barely get out of its own way.
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Coolant leaks at the back, upper and lower corners of the heads is very common. The larger water port from block to head is at the rear of the #7 and #8 cylinders. There is only a vent hole on the front of the heads.
130 psi is alittle low, should be 150-165 on fresh rings and newly lapped valves. I strongly disagree with whomever said not to plane the heads when you have them off. If they have never been off the engine, they are sure to have slight warpage. We're not talking huge, but runout of .0015 is enough to cause it to blow once reinstalled on a new, composite gasket. Have them sent out to any GOOD automotive machine shop. Instruct them to "Plane to true". this is a minimal cut. While the heads are off, pull all the vavles, keeping them, and the springs, in order. Lap them with fine lapping compound. You don't need any fancy equipment. Lightly smear the valve face, drop the valve back in, and hand chuck your cordless drill on the stem and spin with light pressure, moveing the valve on and off the face. Clean all lapping compound well before reassembly. Replace the stem seals.
When you get the heads off, check for any sharp ridges on the cylinder wall, about 1/4" down from the top of the joint face. If it's severe, it will be a possible source of your low compression. Also, if it's severe, check the bore for ovality ( not the rich chocolate breakfast drink; as in 'out of round')
FWIW Liners in LR (or any of the GM, Buick blocks) do not 'drop'. They can't, as they bottom out on a counterbored step. They become loosened when the engine is severely overheated, and can move up, the thickness of the head gasket.
As Okie said, you can do this job in the car. Getting at all the bellhousing bolts is a major pain, unless you have a sixpack of midgets on the payroll.
PS: Lifters aren't that expensive. And they will be worn. So too will your cam, but that's a step beyond.
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One more thing I will mention. There are several schools of thought on the new, composite (as opposed to the older, waffle steel ones) Head gaskets.
Many insist that you should plane an additional amount off, beyond true, to compensate for the apparent increase in the thickness of the gaskets. Others disagree. Whichever, the compressed thickness of the new gaskets isn't much more than the old ones, and any reduction in performance, becausee of possibly lower compression is, in my thinking, more perceived than real.
Having said that, I will say that I scratch built one of these 4.2s for my 110, and chose to take an additional. 020" off beyond true. That may seem like a huge amount, and in the grand scheme of Land Rovers, may be. However, I was making some other performance mods, and was looking for, and got 9.5+:1 compression. I know of one other 110 that may outperform mine, and it has a 5.2 in it. Punching this, in fifth, is worth standing up and taking notice.
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No ignition mods. I happen to like the lucas distributor. I run 12.5 degrees of advance. Centrifugal weight springs are TVR part numbers, but still 34 degree I think.
Cam is a GM part for the Police Interceptor 400, NOS and 20 years old.
Flat wound valve springs and counter springs. (So I wouldn't have to trepan the spring pockets)
Perfect Circle piston rings. All rods balanced to .18 grams.
Flywheel cut .325" (8 pounds removed)
Modest port matching to the stock exhaust manifolds. Didn't get carried away as I still am trying to find some stainless extractors with provision for cats (and O2 sensors)
That's about it.
And no, I don't run super, just midgrade, but yes, I have to reset the timing to pass CT emmissions.
I strongly disagree with whomever said not to plane the heads when you have them off.
Terry, I didnt recommend NOT planing the heads, I just chose not to
The shop (local GM/Ford/Get er done repair shop) did the head work. I asked them NOT to do this because I didnt really trust them. Unfortunetly I was pressed for time and $ and this is what I did. Plus, I didnt know of anyone else locally who could do this work. Fortunely no leaks so far!
So I agree with your statement about planing the heads.
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Quote:
Originally Posted by sven
Terry, I didnt recommend NOT planing the heads, I just chose not to
The shop (local GM/Ford/Get er done repair shop) did the head work. I asked them NOT to do this because I didnt really trust them. Unfortunetly I was pressed for time and $ and this is what I did. Plus, I didnt know of anyone else locally who could do this work. Fortunely no leaks so far!
So I agree with your statement about planing the heads.
Sven,
My aopolgies. I went back and read your post again, and had I taken the time to read it properly the first time I surely wouldn't have said it the way I did. I am frequently a dumass, as my kids will readily point out.
I am frequently a dumass, as my kids will readily point out.
Haha, he's not kidding. (sorry, but you set yourself up for that. )
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Head gaskets on a 4.2L
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