1987 Brougham 307 V-8

[bil.dun]

Hi Guys, back again for some advice.....I just purchased an '87 Brougham, really nice shape, it may have only 29k miles, but I'm unable to determine if that's accurate. The car has sat unused for much of it's life. I know often that's a big red flag, but it ran well, drove good, and I couldn't resist. What my problem is, is that I drove it about 200 trouble free miles, excluding the shrieking fan belts, which I've ordered online to replace. Started right up, idled smoothly, braked well. I had the oil changed, and added i can of seafoam to the tank. I drove about 15 miles, got it on the highway to help burn out all the carbon and junk, and before leaving the highway exit, it started running rough, I got off the highway, and it was really running rough with a very rich smelling exhaust. I brought it to the local GM dealer, they looked at it the next day, and came back with no compression on the #6 cylinder.....all others were fine. The diagnosis was broken valves on that cylinder, and was told that was a common problem on these 307's, and the mechanics opinion was these engines were junk, and the Chevy 305 was a much better engine. I was quoted $500 just to tear apart enough to ascertain this is the problem, and about $2000 / upwards to repair. Needless to say, it made me sick, I lost some sleep, and also the mechanic offered me $700 for this nice car.                  So after several days of thinking this over, I'm thinking of selling the car for parts or fix, but wondered, what if it's only a sticking intake and/or exhaust valve, and would I dare get into the engine myself, and remove tons of wires, brackets, hoses, and whatnot, remove the valve cover, and check for sticking valves? I'm sure some of you guys have experienced this problem! Any advice? I really do like this car, it's in my mind the CLASSIC Caddy, and I would like to keep it, I just can't afford to sink a fortune into it....I know that's every car lovers dilemma...any advice or input would be greatly appreciated, I'm having it towed back to my house in a few days. Thanks, Bill

[Bruce Nunnally]

Moved to General Cadillac Forum (posted in Tips)

[OldCadTech]

Bill,

Hard to say, but if you were running it hard to ...

On 9/3/2017 at 4:06 PM, bil.dun said:

I drove about 15 miles, got it on the highway to help burn out all the carbon and junk,

You may have loosened a chunk of carbon and it got stuck in the valve port and is keeping the valve from closing.

I would do top engine cleaner and hopefully it will dissolve it. You can rent a bore scope and look into the cylinder through the spark plug hole, prior to doing the top engine clean.

I'm almost positive 87 RWD Brougham had the 305 engine, so I'm not sure the tech had all his ducks in a row when he made that statement. I was working on the line in 87 and I don't recall a lot of problems with the RWD Broughams at all..

[bil.dun]

Hi, thank you for your response...you worked on the GM assembly line? What could be cooler than that, seriously! But anyway, I'm having the old girl towed home today, and in bits and pieces will start removing all that's in  the way of the  valve cover, remove it, start her up, and see if a valve(s) is sticking, hopefully not broken......is there a product you could recommend that will free up that valve? I've seen seafoam being slowly poured into the carb on online videos, and marvel mystery oil being used as well. It seems that if you pour it in slowly, with the engine running, it could cause a fire...but it did seem to work in the videos.  If one were to research the 1987 Brougham, it does indicate that they used an olds 307 this year, and a chevy 305 as well, it could be determined which engine you had by the VIN....mine is an olds 307, according to the engine code. Any more advice from you and other readers would be GREATLY appreciated !!  My last resort, is to sell her for parts, or repair, at a huge $ loss for me, as well as losing my sweet old "87...Thanks again, Bill

[OldCadTech]

No, I worked at a dealership. Sorry, it was a little bit of work lingo. I worked what they called heavy line / A/C which is engine and running gear and air conditioning repair.

I'm not sure it is still available but GM had a product called "top engine cleaner" which we used to clean carbon from the engine and I have used it to fix vehicles with your symptoms. It is a lot cheaper and easier than disassembly of the engine. 

It is easy to use, BUT some people would get worried for their engine if they were watching and/or listening. Check you-tube, maybe someone has posted a video. I will say, for it to be effective make sure the engine is at operating temp and let it set for the recommended time ( 15 mins I think )... then rev it up like you stole it, but do not exceed rpm limits, use quick throttle snaps do not hold the engine at high idles.

I've used the top engine cleaner more times than I can count and NEVER had a flare up. If it's used correctly you should be fine.

I still don't remember any concerns with the Olds engine either. I'm thinking he was giving a personal opinion.

[bil.dun]

Thank you so  much for your input, O C T .....I may not be able to find the GM product, but can't wait to give it or something like it a try. I'll post the results. You know, I think the old girl is growing on me, I've briefly considered selling my '99 Deville in near pristine condition, 51k miles, to pay for the repairs on this old gal! It seems totally crazy, but, I guess that's what us old car buffs do sometimes...if you want to view the car, you can see it listed on ebay for a few more days, I just wanted to see what kind of interest it brought, I may just take it off and keep it ( especially if the sticking valve clears up)  Thanks again, Bill

[barczy01]

The Olds 307 Y engine was indestructible if oil was changed.

[bil.dun]

I wondered if you guys could clue me in on something....before I had this trouble, I bought the car knowing that it would need new belts, as it squealed like a you know what when first started, then after a short while, it would stop squealing, rev up a little, and run smooth and quiet. Now after this scenario, the squealing is worse, and it seems as though maybe a pulley driven component is causing the belt to squeal, until it decides to turn freely, and the component I suspect, is to the left of the AC compressor, just slightly above it (looking from the front of the engine, of course).  Is that the "air pump"? And would that cause the belts to squeal, until it started operating properly, and also cause the engine to miss? I haven't taken a compression reading on the cylinder that the mechanic says has no compression, but I will in the morning. I'm not so sure the GM mechanic was 100% honest in his "diagnosis", as he had a personal interest in the car, and basically offered me a few hundred dollars for it....thank God I'm not that stupid...Any ideas? Is there an "air pump in this engine? Thanks for your replies, Bill

[OldCadTech]

Probably loose belts or worn belts. When it runs for a while they heat up and expand and the noise goes away. I would put new belts on and see how it sounds before blaming any components.