'97 LC 238,000 mi Compression test #'s - what to do?

[drnls]

I purchased this from my wife's sister in 2000 with 90k miles. It was my DD until April '14, then only driven 1-2x month on weekends. It has always been a great vehicle, but burned/used oil, slowly increasing thru the years - eventually having to add a quart every 600-700 miles. No leaks, some seepage - probably upper oil pan arch (according to Beno). Last month I decided to clean it up and start driving again - so far cleaned the interior and front/rear axle job. Sunday I did compression test with these numbers:
1. 205
2. 210
3. 200
4. 200
5. 190
6. 185

From reading other post about compression tests mine are strong and as expected #6 to be lower.
Do I need to do the leak down test or will rebuilding the top end more than likely take care of my oil loss issue? Coolant and oil do not appear to be cross contaminated, engine temp at 180 on hot days.

Other issues - body needs painting, planned on Monstaliner lower 1/3 and roof - then paint whats left. 3rd brake light is out (did not pass inspection) - ordered diode for lights.

Suggestions? I need to decide while I have time with current DD and can take my time on major repairs. My other thought was to sell it and current DD and buy a newer 100 series.
Thanks,Nelson

 

[Comet]

Beno is the man! With that being said, I had similar compression numbers but was burning that much oil between gas fill ups. I had the valve seals replaced in the head and it took care of the issues of burning oil. The diagnosis was made by driving down the road, letting off the gas, getting back on it, and seeing the smoke coming out the tailpipe. On checking compression, did you start at cylinder #1 and work back towards #6? The reason I ask is that I got descending numbers like yours until I hooked up a battery charger to ensure a good fast starter for each cylinder.

Zenor diode if I remember correctly? That's a simple fix. Gotta love MUD.

 

[drnls]

Zener diode is on order and yes front to back. You did basic head gasket job?
Thanks, Nelson

 

[LINUS]

I'd maybe change the oil now & Blackstone a sample - do a full leakdown test if it makes you feel good.

The HG is probably the only thing getting tired & even that is such a known thing to the point you could probably drive this for some time to come & not have a issue.

Back when these were far newer & were primary transport for alot of us the HG job was a bigger thing, but now most 80's are a pleasure/2nd vehicle, so if you pop the HG it just means you know what you're doing over a weekend (or your next paycheck).

Esp if it was sitting & you went to the comp gauge cold, those #'s aren't cause to worry.

Oil, gas, drive.

 

[Comet]

Yes and no to the basic head gasket job. I only had the upper end refreshed by someone WAY MORE COMPETENT than me. A little machining work on the head and a refresh of seals. The bottom end was still in great shape mechanically so I just took everything out, cleaned it up real nice, measured the consumables for wear, had the block checked, and put it back together with new seals/gaskets so she would stop marking her territory everywhere we went. At 340K I swear it looked like someone had been in there before because everything looked new. Granted, there was a lot of cleaning of parts but...

If I were to do it again, I wouldn't change a thing. I have a much better understanding of my vehicle and it doesn't drip everywhere.

 

[drnls]

Compression test was done with engine at operating temperature.

 

[LINUS]

Yes, you're using oil - but stem seals are usually the reason (granted a qt / 1-2K is more common).

But really if your HG was the issue you'd see a 20-40# number on cyl 6, if it blew like everybody elses.

Are you looking for the smart/less expensive way, or are you bound & determined to open this thing up & empty some of your wallet?

If you want to empty the wallet - then heck, by all means. I used to go with the thought that a HG as PM was fine when these were still $20-30K rigs. So for me to say "fill'er up & drive" is a real 180* from a decade ago.

Now it's not such a big deal, and most don't want to dump a load of money at it - but I bet it's just the stem seals eating the oil & you could go a long time before the HG really became conversation. Sounds like it's your pleasure vehicle so it doesn't need to be your 'only way I get to a hospital in a holocaust' -rig.

-your money, your priorities.

 

[drnls]

I am not really concerned about the head gasket at this point - more about oil usage. And yes, you can buy a lot of oil for for how much it costs to do the repair. I am contemplating fixing it up - paint, new leather on front seats, replacing valves/stems/seals (for oil usage) then the head gasket at this point is PM - and making it my daily driver again. Right now I have a 3rd vehicle so the repair would not be rushed vs waiting till I have to do it and I have to rent a car; or sell it and my current daily driver (2011 suburban) and move up to a 100 series.

I love to drive it but not knowing how long till something is going to go, hate to always be slightly concerned..but at 238,000 miles.... of course you can say that about anything.

Nelson

 

[Comet]

I agree with the change in focus that @LINUS speaks of. I have always focused on mechanically sound ideals over pretty things to drape my equipment in (insert really tasteless joke here). My breaking point was the drastic and sudden change in oil consumption. I believe I spent way too much money stopping leaks that would not have disabled my truck but the experience and the steep learning curve was worth it to me. You could go either way with oil, gas, and drive or throw piles of money at an incredibly robust design to fix what may or may not be a big issue. There, I have come full circle and said nothing.... geesh.

 

[drnls]

Thanks, for nothing

 

[Comet]

Thats why im here

 

[LINUS]

Thats why im here

Isn't that why we're all here?

We can enable or give a gut check, sometimes all in a single post.

Srsly, OP - your call, but in the current 80 climate I'd sooner quantify the path the oil is taking to escape & identify/monitor. Not throw scads of $$$ on a HG & head decking/ x-angle valve seat grind & new stem seals (99% of HG jobs stop there & are awesome, mine included).

But if you're about to go 'active duty' with your 80 & need that 'BFE peace of mind', then you do the HG. Your call. Again - it's your wallet.

On the backside if you're selling after running a ton of miles on your terms, a update HG is always a selling point. I'd be lying if I claimed I'd have bought my 40th AE if it didn't have that Robbie/Slee HG receipt for a new one (was done 36K before me, had a 350K odometer). So a documented HG has value, just not 100% payback.

Your 80, your $$$

 

[Tools R Us]

...
Suggestions? ...

Drive it, oil is much less expensive and easier than major engine work? If it's not using coolant, the head gasket is good, run it!

 

[bloc]

If you really want to do the seals I've read of a method where you feed a length of rope into the spark plug hole then turn the engine to compress it into the valves. This will hold them up tightly so you can remove springs/keepers and seals. Once the job is done in that cylinder turn the crank back and pull the rope out.

Tricky bit would be building a tool to compress the valve spring while allowing removal of the keeper.. and not having the cams installed. Meaning you'd have to find a way to use the cam bearing cap as an anchor point or something. But.. that can be overcome.

Oh and make sure you don't drop a keeper into the oil drains to the sump. It won't go through your strainer but can cause a lot of damage if it gets wedged into a connecting rod or something on its way down. Plus you'll have to find a keeper, and your shim on that valve may no longer be correct.

Way more work than just putting oil into it.. but a lot less than a head gasket and it'd fix that particular avenue of oil consumption.

 

[Heckraiser]

I fall into the "keep filling her up and don't worry about it " camp. Seriously, so much of what I post on here lately is followed by the smiley, I'm considering pulling a few teeth out

 

[drnls]

Bloc - that sounds way too risky for my lack of mechanic abilities. I have read about that procedure in the past. Thanks though.

 

[Daniel Calu]

are you sure your not leaking any oil , when I got mine it had many leaks .

 

[drnls]

are you sure your not leaking any oil , when I got mine it had many leaks .

Yes, had it since 2000. There is mild seepage - read original post.