I am having problems with repeated front cover and water pump gasket failure on my 90 Deville 4.5, disassembly and inspection shows that the gaskets have split and cracked around the larger bolt holes and slight front cover distortion. The FSM specs are 30ft lbs for the large wp bolts and 5ft lbs for the small ones. Are these correct torque specs? At this point I have straightened the cover and installed a new set of Felpro gaskets and under torqued the bolts to 50% of FSM spec. I am afraid to torque to spec as I don't want to spend the rest of my life replacing failed gaskets on this car, but also have had these bolts loosen in the past as well. The Felpro tech guy said to get a torque wrench that reads in inch lbs, I now have 4 torque wrenches and don't think that accuracy is the problem. Any help with this would be greatly appreciated.

I really don't trust torque wrenches at anything less than 50-60 ft lbs. I broke a bolt once waiting for my torque wrench to read 40 ft lbs or so and I said never again will i trust them on light duty stuff. I have much more confidence in my wrist torque readings. 30 ft lbs is moderate wrist torque on a 3/8 ratchet. After many years experience my wrist knows how much torque it takes to damage a gasket. I have seen gaskets that I have removed that had blue silicone on them and the silicon seemed to actually reinforce the original gasket. It's kind of tricky to not get too much silicon on a gasket and I try to avoid it in all but the most extreme circumstances. I just pulled the heads off an engine this summer and several of the cooling holes were plugged with blue silicon. It wasn't my doing but it made me re-think my use of silicon and to avoid it or be extra careful in the future.

Are you sure it is 30 ft/lbs and not 30 in/lbs?

I am using a Cadillac manual and it definately says 30 ft lbs and 5 ft lbs. I also have a Chilton manual that calls out 15 ft lbs for the front cover and nothing for the water pump. The Felpro tech guy said to use an inch lb torque wrench because the ft lb wrenches were not accurate at the lower settings but I found that the in lb wrench to be fairly close to the ft lb wrench.

The water pump has a 1/8 ridge as a sealing surface and the bigger 30 ft lb bolts cause this to cut right through splitting the gasket around them. These are 10 mm bolts (15mm wrench) that go through the water pump and the front cover into the block sandwiching the front cover between the water pump and the block. I would be the first to admit that it certainly looks like it was over torqued but am at a loss as to what specs to use.

Felpro seems to have a monopoly on gaskets in the central ohio area, they say made in USA but I'm wondering if it could be Chinese mush causing the problem.

I called the Felpro tech line back and they say the generic torque for the large bolts (10mm thread 15mm wrench) is 12 ft lbs to 18 ft lbs. Could the Cadillac manual be WRONG?? Oh well, this job has 28 bolts and nuts in a delightfull array of sizes and types, won't be getting bored here! I'm thinking of getting a case of beer, drinking the beer and then making a gasket out of the cardboard case!

Could the Cadillac manual be WRONG??
I have found mistakes in them before.

If the front cover is distorted (warped a bit), you may continue to have gasket problems. Is there a way to make it flat again? Like with a little tapping around the bolt holes etc?
You might try two gaskets on there, with a bit less torque. Two gaskets may mate with a warped cover better.

I was able to straighten the distorted front cover with a ball peen hammer and a dolly. I called the Felpro tech line again and they said that standard torque for the 10mm (15mm wrench) bolts would be between 12 and 17 ft lbs. So I guess that the Cadillac FSM spec of 30 ft lbs was wrong and probably was the cause of the distortion and gasket failure. I am going with 12 ft lbs/10mm bolts and 3 ft lbs on the small bolts with med thread locker on all threads and a light coating of RTV on both sides of the gasket. While working on the front cover I noticed that the heater pipe running under the eng is rusted and leaking, so that will have to be replaced before filling with coolant and checking the wp repair. Thanks to all who commented.

Just wondering, for future reference why was this post moved and where was it moved to? I am new to this site and would like to get it right. Thanks again.

That heater pipe under the engine seems prone to rusting, more so in states where salt is used on roads. I sand blasted mine and repainted it three years ago, and it needs it again. I thought about using a length of hose under there, but haven't tried that yet.

The Cadillac dealer says those heater pipes have been discontinued. I did consider running heater hose the whole way but am going to Lowes to look at plumbing supplies, brass would work. I'm not sure about copper. Plastic pipe would also be a possibility, the radiator side tanks are plastic. A sarcastic attaboy to Cadillac for designing such a reliable and common sense way to route those heater pipes, built to fail!

Copper tubing may not be the answer. It's prone to cracking near fittings if there is much vibration involved. As it vibrates, the metal is sort of fatigue hardened. The heater hose should work fine, and it's made for that environment.

You are probably right Steely Bill, copper is not the answer! Using a part # from this site I was able to get some tubes from Cadillac but they were not correct. Heater hose would work, as least for a while. I was thinking of trying stainless braided heater hose, at least it wouldn't rust and is rated for high temperature. Cadillacsonly.com says they have the correct pipes in stock for $100 but you can get 6 ft of .750 stainless braided heater hose for $20 from Jegs. Since times are so hard and all I'm leaning towards the $20 solution at this point.

The stainless covered hose should do a good job, with the stainless covering preventing chafing down under the engine.
A few clamps and/or a bracket on it to hold it in position may be a good thing to do where it hangs under there.

The stainless braided hose is just heater hose with a braided stainless cover, it certainly looks better than regular heater hose. I was able to clean and reuse the front section of heater pipe to avoid routing problems around the AC compressor. It should be an effective repair, particularly under the oil pan where it is exposed to whatever kicks up. Just noticed the trans lines are corroded, may as well replace them while I am at it.