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My '97 Eldo


BigCat83

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Hi everyone,

I've been commuting to work in my '97 Eldo (70 miles RT) and losing a qt. plus of coolant every day

for the past month and a half and going through a qt of oil a week. This past week the temp gauge started to really, really climb several times and after much delay, research and discussions with a few local shops (Lutz, Fl area; are you sh!ttin' me! Talk about scary!!!), I decided to tackle the job myself. I'm an experienced amateur and ex tech school trained pro tech so I know what I'm doing (perhaps I do) ...

I started my repair this afternoon. Successfully and easily removed the intake manifold and all of the attached parts, etc.

My car has 91.5K on it and so far this is what I've found:

8 of the 10 intake manifold screws were loose, found evidence that a ham fisted mechanic (dealership "mechanic"?) had been there before me. Under the intake manifold on the right end was a HUGE oil soaked mouse nest. That entire end of the block valley was drenched in oil!!! I found no strong evidence of a serious external oil leak. And NO evidence of an external coolant leak into the valley. My assumptions are that one or both HGs have deteriorated internally, or that head bolts have pulled. I started having problems right after a spirited Italian tuneup after work one night.

The car is burning oil - the backside of the throttle plate is covered in an oily black sludge (oil soaked carbon) the inside of the intake manifold looks like it's covered in the same goo. I've worked on many Alfa Romeo I-4s, V-6s and Jaguar V-12s (sweet motor) over the years and have seen similar symptoms in those cars when they've need a top end rebuild. I really don't think my Northstar needs a top end rebuild, however...?

I am going to timesert the block with the engine in the car (have all the tools but not the room in the garage to drop the cradle or pull the motor from the top). I have begun taking many digital pics and will post all of my experiences with this project so that everyone else can benefit.

Ta Ta for now... :D

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The car is burning oil - the backside of the throttle plate is covered in an oily black sludge (oil soaked carbon) the inside of the intake manifold looks like it's covered in the same goo.

What you are seeing on the backside of the throttle plate and inside the manifold is normal. It oily residue from the crankcase introduced via the PCV system. You may infact be burning oil, but this is not evidence of it.

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The car is burning oil - the backside of the throttle plate is covered in an oily black sludge (oil soaked carbon) the inside of the intake manifold looks like it's covered in the same goo.

What you are seeing on the backside of the throttle plate and inside the manifold is normal. It oily residue from the crankcase introduced via the PCV system. You may infact be burning oil, but this is not evidence of it.

Good point...

Thanks, I've always been anal about maintenance and change PCV with every second oil change.

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Replacing the PCV valve is a TOTAL waste of money - all you really need to do is clean it in solvent if it needs it and it rarely does...

Be sure to have a helper handy when removing the heads - they are heavy and do not set them face down on the bench or you will bend the valves. Leave the exhaust manifolds attached to the heads.

I did the same job in early April on the '97 STS I bought - I was going to Timesert it with the engine in the car but decided to pull the block - it only took me an extra 30 minutes and it makes the Timeserting and reassembly a LOT easier. My garage has 10'6" ceilings and I used an engine hoist (cherry picker) and it went just fine. If you have room to open the hood, you have room for an engine hoist. I didn't remove the hood - I just removed the passenger side wiper arm and the hood support cylinders and then raised the hood to a vertical position and tied it off to the garage door track. That worked great and there was no need to store the hood or go through the realignment procedure.

If your engine is leaking at the oil pan or crankcase half, this is the perfect time to install the updated gaskets with the anerobic sealant - the engine will be spotless and not leak a drop afterword.

If you run into trouble, there are many of us on this forum that have done the same repair - we will get you through it.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Perhaps I'll take your advise re the PCV...

How much does a complete cradle assembly weigh?

I have an engine hoist and a motorcycle/atv stand (1500# cap. I think), I may be able to lift the car body high enough on one side and pull the cradle out from under it on the other side. I can't pull it out the front because my driveway slopes right at the garage door...

Of course when I lived in Massachusetts my garage was HUGE and I would have had plenty of room to do this job...

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I HIGHLY recommend dropping the cradle. You will save a lot of time and grief if you can do the timeserting with the cradle out.

The cradle is reasonably easy to drop...easier than pulling the engine out the top...and serves as an engine stand.

The extra time to drop the cradle will be more than made up in the time you save doing the timeserts.

How much room do you have in front of the car as far back as possible?

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I have done two Northstar head gasket replacements, and guided several others.

Among the most important things that you need to do are:

1. Get the OEM service manuals, this will stop you from:

__.Unnecessarily disassembling anything

__.From destroying parts due to lack of understanding on proper assembly and tightening techniques.

2. Have a good size area to remove and clean the parts.

3. Do not attempt do do this repair with the engine in the car.

4. Handle the heads carefully, they are most likely fine, and just need cleaning. Use care when cleaning to NOT scar the head gasket surface when scraping, or removing the alignment dowels.

The Timeserting itself is not to hard, but take care and protect the engine from drilling's and tap debris. Rinse the new tapped holes with spray brake cleaner, the blow out thoroughly with compressed air. Follow the Timesert directions carefully.

I used thinner to clean some of the parts and (believe it) Wesleys Bleche-Wite to clean anything that I could spray-rinse with water, a very potent degreaser.

Torquing the new head bolts is critical. Follow the proper service manual techniques and do not allow distractions to interrupt the process.

Re-positioning the oil pump, and tightening the vibration dampener, very critical. If not done right the engine will fail VERY quickly. The vibration dampener provides the "pinch" to the oil pump rotor, not enough and no oil pressure, too much = broken bolts and/or vibration damper damage; also very bad.

The cars I have worked on were 93', 94' and 95'. There are some differences compared to yours, but the basic method of disassembling, cleaning, and timeserting is the same.

I have a number of notes that explain in more depth, if you are interested send me a Private Message, and I will forward them to you.

Attached is the list of parts that were required to do the Timeserting and in my case the oil pan gasket, you should expect a similar list and cost.

I highly recommend using OEM gaskets, these engine run much hotter routinely than most engines, the OEM gaskets were designed to handle these extremes.

-George

1993_Cadillac_Northstar_Head_Gasket_Repair_List.pdf

Drive'em like you own 'em. - ....................04 DTS............................

DTS_Signature.jpg

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George's list is very thorough- I think I used it when I did my '97 STS. Your '97 engine won't need the phenolic spacer gaskets and you can reuse the intake manifold gasket if it is not damaged when you remove the intake.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Thank you fellas...

I was very carefull in removing the intake manifold and the gasket seems OK - I'll check more thoroughly later. I do have the factory manuals and use them.

I really don't think I have any choice but to do this with the engine in the car. I just don't have the floor space to pull the cradle out from under the front of the car...unless it will come out the side. There are some fellows who have posted about their successfull experiences with doing this job with the engine in the car, so apparently it can be done.

I truly am gratefull for the help and encouraging words.

To digress a bit...when I should have been home working on my Eldo I spent this afternoon with some friends at the Tampa Auto Show. We spent much time at the GM exhibit. It's obvious that GM has spent a lot of money upgrading the Cadillac and Buick brands, Pontiac to a lesser degree and lowly Chevy...

Cadillac is truly world class now and can compete with the best of Europe and IMO provide more value for the dollar. I had my *smurf* glued into a black on black '07 XLRV. What a ride!!!!!!!!! :D

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