: Strange compression test results, oil inside intake manifold & smoke !!



Deville Concours
03-04-13, 05:43 AM
Hi ...
I bought cadillac Deville Concours 1999 models before 3 months and the mileage about 100.000.
And here's my story...

The car has several problem in engine
Backfire + weak + shaking
I have changed spark plugs and spark plugs wires + clean throttle body, clean fuel injectors , change fuel filter , air and oil filter and others things.

Now the engine is better than before and the backfire has gone. But it is still shaking and it's a little bit weak especially when start driving between 0 to 30 and after that it becomes better.
The problem is when i drive the car for a long distance , parking my car , stop the engine (or keep it running) ,and after few minutes drive it again a lot of smoke comes from exhaust and the smoke stop after a minute ( the smoke only comes after stop ).

I decided to do compression test to know what is causing engine smoke and change intake manifold gasket because there is leak on it and i think it makes the engine weak and shaking.

After i did compression test the results are:
- In front head (water pump side) cylinders number 2,4,6,8 :
Dry test : all about 160 to 165 psi
Wet test : all about 170 to 180 psi
- In rear head cylinders number 1,3,5,7:
Dry test : all about 200 to 205 psi
Wet test : all about 210 to 220 psi

I don't know why the rear side is higher than front side !!! I retest all cylinders and i get the same results !! Are this results normal ?? Or because water pump fixed in front side make it lower compression than the other ?

Also when i start to open intake manifold to change gasket i found a lot of black oil inside it. I checked pcv valve and it is ok and i dont think it is this much bad . I don't know from where the oil comes , but i think it makes the engine smoke , so how can i fix that.

I need your help
What are the compression test results means and why is one side more than anther ?
Why do i find oil inside intake manifold , does this make engine smoke and how can i resolve this problem?

Thank you.

Ranger
03-04-13, 11:35 AM
:welcome:

Overfilling the oil contributes to oil consumption. Keep the oil level half way up the hash marks. NOT to the MAX mark.

Read up on OIL CONSUMPTION and FULL THROTTLE ACCELERATION in the Tech Tips (top left) of the page.

Ranger
03-04-13, 11:35 AM
:welcome:

The oil you see in the manifold is from the PCV system. Overfilling the oil contributes to oil consumption. Keep the oil level half way up the hash marks. NOT to the MAX mark.

Read up on OIL CONSUMPTION and FULL THROTTLE ACCELERATION in the Tech Tips (top left) of the page.

Also check this. http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/107135-river-runs-through-valve-covers-pcv.html

daveyhouse
03-04-13, 10:59 PM
:welcome:

The oil you see in the manifold is from the PCV system. Overfilling the oil contributes to oil consumption. Keep the oil level half way up the hash marks. NOT to the MAX mark.

Read up on OIL CONSUMPTION and FULL THROTTLE ACCELERATION in the Tech Tips (top left) of the page.

Also check this. http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/107135-river-runs-through-valve-covers-pcv.html

Thanks for that link. Now I am glad I resealed mine when I had my covers off. I used the ultra grey.

Deville Concours
03-06-13, 01:20 PM
:welcome:

The oil you see in the manifold is from the PCV system. Overfilling the oil contributes to oil consumption. Keep the oil level half way up the hash marks. NOT to the MAX mark.

Read up on OIL CONSUMPTION and FULL THROTTLE ACCELERATION in the Tech Tips (top left) of the page.

Also check this. http://www.cadillacforums.com/forums/northstar-performance-technical-discussion/107135-river-runs-through-valve-covers-pcv.html

Thanck you for the helpful information it was usefull .
But what about compression test result ? Is it normal ?

Tanks.

Submariner409
03-06-13, 03:04 PM
Hello ! to Bahrain ........

The compression numbers for 2,4,6,8 are normal. The numbers for 1,3,5,7 are 20 psi high - I have no idea why, unless the cylinder head(s) were removed for repair and there was an excessive milling cut done to the right (rear) head - perhaps due to head warping or a damaged gasket surface - or there is excessive carbon buildup in the right (rear) cylinders. You indicate that the left (front head may have been removed, in which case the combustion chambers and piston tops might have been cleaned of carbon deposits.

Have you driven the car at high speed over on the mainland - west on Rt.40 ? If so, how does the engine feel up at 2000 rpm + ?

Manic Mechanic
03-06-13, 03:14 PM
That kind of compression test result and your symptoms are a direct indicator of a camshaft timing being off one tooth. In my compression testing of a 2001 DTS northstar it came in around 190. So you have half and engine higher and half lower. I don't know if that mean you have a good side with higher compression (see if the '99 was the last high compression year, I think it was), and and definately a side with cam timing off that's not building compression. Or you could have both sides off in opposite directions. You are going to have to verifiy all cams to crankshaft timing. If you are a DIY'er you're in for a learning curve and will definately need OEM level repair information, either a factory service manual or a subription to an online repair info site like Alldata or Mitchell OnDemand5. Read through some of the posts on valve-train/camshaft timing to see if you can handle it. It's harder than you think but not impossible if you're handy with engines. If not ask the forums for the name of a good Northstar shop in your vicenity.

Vernon

Submariner409
03-07-13, 10:49 AM
He's in Bahrain. NO shops. He's using either an online language translator or an interpreter or he's learning and getting pretty good at English.

Manic Mechanic
03-07-13, 02:22 PM
He's in Bahrain. NO shops. He's using either an online language translator or an interpreter or he's learning and getting pretty good at English.
I understand.

Deville Concours, I have a question for you. Are you able to understand me or recieve a good translation of my posts? I have the ability to choose my words in a manner that is easyer to understand or translate. This may be of some help to you if American English is not your primary language or the translation software isn't able to work properly with my usual writing style.

My regards,
Vernon

Ranger
03-08-13, 12:34 AM
He's in Bahrain.
:hmm: What am I missing? How did you come to that conclusion?

Deville Concours
03-08-13, 07:30 AM
Hello ! to Bahrain ........

The compression numbers for 2,4,6,8 are normal. The numbers for 1,3,5,7 are 20 psi high - I have no idea why, unless the cylinder head(s) were removed for repair and there was an excessive milling cut done to the right (rear) head - perhaps due to head warping or a damaged gasket surface - or there is excessive carbon buildup in the right (rear) cylinders. You indicate that the left (front head may have been removed, in which case the combustion chambers and piston tops might have been cleaned of carbon deposits.

Have you driven the car at high speed over on the mainland - west on Rt.40 ? If so, how does the engine feel up at 2000 rpm + ?


That kind of compression test result and your symptoms are a direct indicator of a camshaft timing being off one tooth. In my compression testing of a 2001 DTS northstar it came in around 190. So you have half and engine higher and half lower. I don't know if that mean you have a good side with higher compression (see if the '99 was the last high compression year, I think it was), and and definately a side with cam timing off that's not building compression. Or you could have both sides off in opposite directions. You are going to have to verifiy all cams to crankshaft timing. If you are a DIY'er you're in for a learning curve and will definately need OEM level repair information, either a factory service manual or a subription to an online repair info site like Alldata or Mitchell OnDemand5. Read through some of the posts on valve-train/camshaft timing to see if you can handle it. It's harder than you think but not impossible if you're handy with engines. If not ask the forums for the name of a good Northstar shop in your vicenity.

Vernon



Thanks for your reply.

All possibilities are open , actually before I bought this car I was looking for Cadillac fleetwood 1979 to 1991 but I didn't find a good one that worth work on it as a project to restore and clean cars are really expansive because people like this models more than the newer models , I was looking for a project car. Cadillac is very famous car in my country but it also rare to find in our roads because it can't survive with our wither (I mean the hot summer). So it hard to find the old models . however I have found this car ( I know it's not that much old but it also uncommon), What encouraged me to buy this car is that it has a straight body , good paint except front and rear bumper, low mileage and its price. Maybe you don't believe me if I told you that its price was about 600 $ when I bought it .

This car is not my daily used car, I have Nissan Altima 2009 for daily purposes but this kind of car doesn't give you the American driving experience especially the old American cars such as Lincoln town car , Crown Victoria, chevrolet caprice and others. In the past I owned a Lincoln town car 1993 it was really comfortable an strong in the same time and it was a magnificent car.

The person whom I bought the Cadillac from didn't use the car for about one year and when he was using it before ,he just drove it for very short trips and maybe once a week. And you know if a car like this was left without using for along time a lot of problems would happen in the engine, the carbon one of them, and I can assure you that the engine is in its original state since it left the factory ( no body open it ) and also i can assure you that it has a lot of carbon inside it ( if you have a good and easy Method to take out this carbon please mention).

Now I already open intake manifold , right (rear) valve cover and all cooling system (water) hoses because I have water, air and oil leak from this parts and to fix PCV , all that without take out the engine. Also I didn't finish working yet.

I don't have a perfect experience in repairing cars' engines but I have some. The northstar is new to me that's why I'm asking you about it .

----------


He's in Bahrain. NO shops. He's using either an online language translator or an interpreter or he's learning and getting pretty good at English.

Ha ha ha ha*:lawl:
Why do you say that ? :canttalk: I'm not living desert :tisk:. We have everything that you have in us . I don't know from where you get this information.




There are alot of shops in Bahrain but they Don't prefer to work in northstar and *others need a lot of money for just small jobs . Actually I want to work in this car *myself and I am happy to do that. Northstar is uncommon in my country and it's hard to work on , that's why they don't prefer working on it especially if they didn't do that before . Also, northstar *a really powerful engine but it *has a common problem which is overheating, so many people avoid spending a lot of money on it.




I understand.

Deville Concours, I have a question for you. Are you able to understand me or recieve a good translation of my posts? I have the ability to choose my words in a manner that is easyer to understand or translate. This may be of some help to you if American English is not your primary language or the translation software isn't able to work properly with my usual writing style.

My regards,
Vernon

Vernon :
Thank you for your cooperation , I know my English is not very well and I have some mistakes but they are not that bad. I can understand more than my ability to express. Don't worry about your language . It's really clear and I can understand Each character you type. :cowboy:

Ranger , Submariner409, Manic Mechanic
I'm very grateful for your interaction and cooperation.
I appreciate that.
You are great people

Ranger
03-08-13, 12:12 PM
Vernon :
Thank you for your cooperation , I know my English is not very well and I have some mistakes but they are not that bad.
Your English (and punctuation) is far better than some posters who are born, raised and educated here. You have nothing to apologize for.

Submariner409
03-08-13, 04:21 PM
Thanks for your reply. Why do you say that ? :canttalk: I'm not living desert :tisk:. We have everything that you have in us . I don't know from where you get this information.

Things must have changed since 1976 .................. U.S. Navy