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It´s time for time serting....


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I have had problems for a while now with a dead cylinder, tried everything to locate the problem. Yesterday I bought a cylinder compression tester and found that it only had about 30 psi in pressure...

Just to make sure I checked with another cylinder and confirmed the loss of compression.

When I bought it 2 years ago I let a shop make a compression test that showed that everything was normal (90 000 miles), silly me thought that it would stay that way for another 100 000 miles, well well :(

I have no mixing between oil/coolant, no coolant loss, no exhaust smoke etc.

That makes me think I´m dealing with a burned valve for example.

It seems like it´s not uncommon on cars imported from germany (according to a something I read on the net from a Swedish source I don´t remember)

I´m going to make some calls to get a fair price for the work, if the are to expencive I might try to do it myself.

I read that Barry94 made the timeserting with engine in place and that would be my approach since I don´t have the space to do an engine pull.

No wonder that my car failed the test (2005:1200 in HC value;2004:100;2003:73;2002:45) :D

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Jan, besides the miss do you have any other symptoms? Overheating, coolant loss, ticking noises, etc? You might want to pull the cam cover and see if you have a collapsed valve spring or looseness in the valve train on that cylinder, if you do you could replace/repair it. Mike

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Hi Scotty

No coolant loss, no ticking noices, no overheating.

A collapsed spring should make some noice i believe?

I don´t have any record on this car from the previous owner(s) in germany, just from the previous owners in sweden. It might just as well have been overheating on the A-bahn for all i know, or perhaps the valves have got corroded from being put in some moisty garage?

Had an old (-57) Volvo military car that only had 27000 miles on the odometer.

only 1860 miles for the last 30 years :D

I had to reface them and the seats and after that it ran as new, it only took a day to do that...wish it was that easy here.

If I´m going to do that myself I will check the springs and valve train, lets hope for the best.

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I called around and the mechanics will do it for 4000-7000$...and that´s in the month of April since they are busy, this is from the ones who are supposed to do "American cars". The support here in Sweden are bad to say the least, the last one I called recommended me an engine from the junk yard, that would be cheaper... :angry:

Like he said with all the ignorance and knowledge of a typical "mechanic" "It´s a Cadillac, those motors aren´t made for beeing serviced, they aren´t constructed that way"

Bah..seems like I have to do it myself then. I can smell fuel in the oil, but since I don´t have any abnormal noices and the spark plug isn´t fouled it seems like there is some kind of combustion, the oil level aren´t increasing either so perhaps it´s safe to drive it the 150 miles to my parents place so I can borrow their garage.

In the mean while I will have to drive the Eldo instead until I get the time and money to do the job.

Here in Sweden a -93 STS like mine is still worth about 12000$ so I will give it a shot.

One big backside of this is that my father will go on like " I told you not to buy a car like that, I can´t believe that valves or headgaskets fails on newer cars like they did in the 60`s etc etc" and I tend to agree with him.

But then again he is used to Volvos (like I was) making 200000+ miles easy without doing jobs like this. I rather change the timing belt every 25000 miles than a headgasket every 130000 its faster and certainly cheaper....

My Volvo 960 had 204 bhp on a 3 liter engine, just about the same bhp/liter as in the Northstar, changing the timing belt on that one took me 30 minutes with a 10 minute break in the middle :D

I really like the STS since it is reliable, smooth, comfy and is a dream to drive. Hopefully the failure is due to neglected/wrong service by a previous owner rather than "a normal thing to encounter at this mileage"

This is the backside of buying a used car, you really don´t know what has happened to it before :angry:

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Hi Scotty

No coolant loss, no ticking noices, no overheating.

A collapsed spring should make some noice i believe?

I don´t have any record on this car from the previous owner(s) in germany, just from the previous owners in sweden. It might just as well have been overheating on the A-bahn for all i know, or perhaps the valves have got corroded from being put in some moisty garage?

Had an old (-57) Volvo military car that only had 27000 miles on the odometer.

only 1860 miles for the last 30 years :D

I had to reface them and the seats and after that it ran as new, it only took a day to do that...wish it was that easy here.

If I´m going to do that myself I will check the springs and valve train, lets hope for the best.

Yes if you had a collapsed spring or valve train problem you would have ticking noise most probably. Re-do the compression test on the bad cylinder and but first inject oil into that cylinder and see if that affects the compression reading. If it does it's most likely a ring problem and not a valve problem.. Report back your results, Mike

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Hi Jan,

When I purchased my '94 in 1997 it had a rough idle. After much checking I determined it was a burned exhaust valve.

I had 55 lbs compression on #5 cyl.

As Scotty mentioned, I injected a bit of oil into that cyl and checked again and only gained about 5 lbs additional.

The car was still under warranty (time) but over the miles by 2K.

A long story about that involved (GM, The Dealer and myself).

Similar to Pat's story. (Another thread)

The end result was a 50/50 deal. They give me the parts and I do the labor.

So I removed the head (rear head - engine in the car).

You could see daylight thru one exhaust valve/seat.

I DID NOT Timesert the engine at that time as I didn't know anything about pulled head bolt threads.

About three years later I had three pulled head bolts on that head.

So... Off comes the head again and timesert the block.

It's been working great since.

If you do the job yourself you will need a few special tools to remove the valve.

I made the tools.

If you are interested I can send you photos of those tools.

Good luck

Barry

2008 STS V8
2016 Colorado Z71
1970 Corvette LT-1 Coupe

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Jan,

Some comments on the compression test:

If the pressure values started low and increased as the engine was cranked, this is a good sign of a piston ring problem. Scotty's comment on adding oil into the suspect cylinder is a good way to confirm this. Add about 3 - 5mL to the cylinder for this test.

If the pressure starts low and stays low as the engine is cranked, this may be a valve or a head gasket. Adding oil to the cylinder will not help boost the pressure too much if a valve is leaking - as backed up by Barry94.

You mentioned

Just to make sure I checked with another cylinder and confirmed the loss of compression

In some cases adjacent cylinders will loose compression when the head gasket fails. If these cylinders were next to each other a head gasket failure is strongly indicated, but you do not seem to have the characteristic loss of coolant that comes with an overpressurized cooling system, so it could be the piston rings.

Hope this helps. :)

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Thanks for all responses :)

I´m planning on doing this later this year because I don´t have access to a nearby garage. Will have to do it on the vacation perhaps.

I´ll have to do an emissions test tomorrow again so that my car will be legal on the road for another month. Found a vacuum hose was loose, perhaps this one caused the high HC reading? Lets see tomorrow B)

If it passes the test I´m planning on selling it since I wan´t a newer one and don´t won´t to work on it more than necessary. If I had my own garage I would be doing it right now, but as it is I´ll have to use others with all the downsides that meens. I wan´t to make things at my place and in my own time. It needs shocks, undercoating, some new leather on the passenger seat etc etc so this would be a perfect time to sell it.

If it don´t make the test, well then I will have to do the job since it won´t be easy to sell it otherwise, but then I´ll keep it instead.

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