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Discussion Starter #1
Hi Everyone
My 76 CDV has a noisy clattering coming from the engine.
We are not sure what's causing this noise.
We have taken the valve covers off and discovered that some of the pushrods were blocked and not oiling. There was also considerable sludge build up on the left bank head. However we have come to the conclusion that this is not the reason for the 'clatter'.
Our local caddy man has sugested putting half motor oil and half transmission oil in the engine to 'loosen' the sludge in the passageways. This has been hotly discussed in a number of places, some folks saying it disturbs the sludge that has accumulated in the bottom of the pan and elsewhere and distributes it around the oil passageways causing further blockages. Opinionms please./
Some questions:
should we drop the oil pan and inspect the bearings ?
Could there be lifter/cam problems ?
any advice would be much appreciated.
Thanks
BlueBoy
1976 Coupe De Ville
 

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Agree with Terrible One. Probably the lifters and possibly the rockers too. You always see this problem accompanied with sludge in the covers. Whoever owned this car did not change the oil very often.

You can try the ATF with oil. However, there is a small risk. I've done it myself many times with Mystery oil and had no problems. As a compromise, you could add a small amount at your next (hopefully soon) oil change. I doubt the clatter will go away with just flushing.

Probably not a bad idea to clean out the pan. I suspect your bearings are OK.

Good Luck.
 

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1970 Sedan deVille hardtop
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well, did you try removing the clogged pushrods and cleaning them out? Although, if you are hearing lifter clatter, I wouldn't be surprised if the lifter needs replacement. That might be the beginning of the fix, followed by keeping up regular oil changes. You are always changing the oil with the engine hot, right?

I dunno bout ATF, but I have used a product called Seafoam before. There are a number of similar products out there, probably no difference. Basically they are a mild solvent and will help dissolve build up sludge. You pour them into the engine when it is hot, let it idle (only idling, no loads at all) for 10-15 minutes, then change the oil and filter. Yeah, it might get some stuff losse from the pan, but that'll all be flushed out when you drain the oil.
 

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Discussion Starter #5
Thanks guys I'm gonna try the ATF/Seafoam trick after dropping the pan and cleaning out the sludge. But before that I'm gonna take off the carb and manifold and check the lifters and cam. I think I should replace the timing gear anyway so after replacing any damaged lifters, all pushrods and timing gear I'm hoping the problem will be solved. If the cam looks at all damaged that will get replaced as well. I'm thinking that while all this is getting done I should renew the water pump. Is it advisable to upgrade the oiul pump and is this a 'big' job ?
Anyone know what a low profile A/C compressor costs and where to get one ?
Merry Christmas to all.
 

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Timing chain replacement is a good idea. The original stock cam sprocket had nylon teeth. These frequently cracked and broke off. You may find some pieces in the oil pan. I always used a steel replacement.

The stock oil pump is very reliable. In fact I never had a problem with one even with high miles. Replacement is a piece of cake, it's externally mounted right behind the oil filter. Others are more qualified as to using a high performance type. For a street machine, I say don't worry about it. However, it would be a good idea to get an actual PSI reading to see if any problems are developing.

Water pump, sure. You'll be pulling off the old one to do the timing chain. This would be the perfect opportunity.

Good luck with your project.
 

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I dunno about the waterpump, just because I like the "if it ain't broke..." philosophy. The WP is right out front, so it is not a pain if it goes bad later. I'd just inspect it, replace only if nessacary.
Definately get the chain though - that was broken from the factory ;) Stupid penny-pinching bean counters...

Honestly, if you plan to clean out the pan and the lifters you shouldn't need any kind of engine flush type product. The point of those is so you DON'T have to crack the engine open. I rate those as an only-if-needed product. I'm sure the can says to use with every oil change, but that's to sell more. If it doesn't need it, just change the oil as normal.
But, do always change the oil and filter after opening up the engine any more than just the valve covers to remove any stray crud that might have gotten in there when you had it open.
 

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I've used the ATF "flush" before. ATF has a lot of detergent in it.It is thin so if you put 50/50 in I wouldn't drive it, just run it. I use 1qt to 4qts oil. It will break all that sludge loose so you have to do a couple of quick oil changes...like a couple hundred miles for the first and a little more for the second. Make sure you change the filter both times.

If I'm doing internal work on a sludged engine I like to do this to get a cleaner environment for the new parts. You definitely have to bump up your oil change schedule or change oils.

I'm curious...How long have you had it? How often do you change the oil? Do you stick to 1 brand? What weight?
 
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