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Low compression - bad valve?; 1993 metro 2dr/hatch 1.0
Topic Started: Feb 16 2011, 06:33 PM (6,012 Views)
93metrochick
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Ok, I took my geo to the shop today with questions about having a diagnostics check on it because it has been running rough at idle, most noticeable after it's been driven 30mins or so. They guys there seemed to be able to know right away that I had cylinder/valve issues simply by the way it was running. After doing a compression test they said that valve #2 had low compression and they said it was "probably a bad valve". I'm new to this area & don't know how trustworthy any shop here is. I have lots of questions about my options & wanted to get some advice since your all Geo owners.

#1. How can you tell it's a bad valve? Is this something that can't be 100% diagnosed until the engine is torn into by someone who knows what they are doing? Is a diagnosis simply by hearing/guessing commonly done?

#2. The guys at the shop suggested replacing the engine as opposed to the valve because it's comparable in cost. Really?! Buying an engine is about the same as replacing the valve... this just doesn't sound right to me?

#3. I have seen some posts on here with psi numbers related to compression tests. They never told me any numbers when they tested mine, they just said it was low on cylinder #2. So, I'm wondering.... is there anything I can do to extend the life of this particular engine until I can afford to figure out what the appropriate repair is for my situation? I hate to sound dumb... but, maybe some sort of additive like the lucas stuff that I add to my oil but something good for the cylinders?

Any suggestions/ideas would be welcomed. Thanks!
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Coche Blanco
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Replacing the engine for a burned valve is stupid, most the time you will replace it with a junkyard engine that has the same problem yours does. It depends on how down and dirty you want to get honestly.
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96Geoman


The head can rebuilt for around $200. The problem is...if the rings are worn, the new valves will not last long. I installed a rebuilt head on top of a worn out block (burning oil / blowing smoke) and it only lasted 6 months.
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93metrochick
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96Geoman
Feb 16 2011, 07:02 PM
The head can rebuilt for around $200. The problem is...if the rings are worn, the new valves will not last long. I installed a rebuilt head on top of a worn out block (burning oil / blowing smoke) and it only lasted 6 months.

My engine doesn't blow any smoke, but I assume that it is burning oil because I have to add oil every two weeks or so. I have no indication of a leak or anything though, which has been a mystery to me. I have no oil on my drive way or caked up anywhere on my engine. But losing oil means I'm burning it somewhere, right?
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Bad Bent
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Yes, it's going somewhere. :-/

Most of us keep records on out gas mileage as an indicator of something going wrong. How many mile do you drive in two weeks?

Actually if you are checking your own oil you probably have the skills to repair your Geo. Seriously. ^o) You can rent a compression gauge at a parts shop and do the compression test yourself. Click on: How to Compression Test.

The other test for valves is to buy/rent a vacuum gauge, some rubber vacuum hose and a plastic "T" connector. There is a Manifold Absolute Pressure (MAP) sensor on the firewall that has a vacuum tube going to the engine the Gauge is "T'd" into the line at the Throttle Body. The engine is started and the vacuum should be 19" and steady. Any flutter is a valve, if you do not have any leaks. You do not have a carburetor. It's fuel injected (one injector).

What kind of oil are you using? Mobile 1, 10W30 has been recommended. A synthetic is good for mileage.

I got a "pressure tested" engine on eBay for $525 shipped, 3 years ago. That's maybe $750 now. The rebuild could cost as little as $250 or up to $700 with new rings and more. Yes, a G10 rebuild kit Includes 6 SS valves, 6 bronze manganese guides, and 6 viton seals. $100 Hand polished valves add $15 as your seals may be bad. Click here.
Edited by Bad Bent, Feb 16 2011, 07:37 PM.
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mcmancuso
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To confirm the bad valve quickly, use a dollar bill or strip of paper, while the engine is running, hold the paper up by the end of the exhaust pipe. If the exhaust sucks the bill in and out of the pipe, it has a bad valve, if it just pushes ut out the exhaust valves are probably ok.
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Woodie
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The simple fact that it is a Metro 3 cylinder and was driven in to the shop "running rough", you're about three quarters of the way to concluding that it has a burned valve. Coupled with the fact that you are burning oil badly, you might have a broken piston. Still no big deal, pretty much the same labor is required.

They're talking about a used engine, which may very well have the same problem. You're better off finding someone who really know Metros do a head job and new rings.

There is no wonder liquid you can pour on it to make it better. You can't see burning oil anymore, the catalytic converter eats up most of the smoke. That burning oil helps to burn the valves and also poisons the catalytic converter with time.
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Johnny Mullet
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The garage can also order a redone head from 3Tech Performance (link on main page) and just charg labor to do rings and the head swap. It can all be done with the engine still in the car.
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GeoStalker
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Johnny Mullet
Feb 17 2011, 07:37 AM
The garage can also order a redone head from 3Tech Performance (link on main page) and just charg labor to do rings and the head swap. It can all be done with the engine still in the car.
:gp
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metroschultz
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Please just call me; "Schultz"

Or maybe one of our SC members can help out a newbie.
Just a thought.
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93metrochick
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Wow, lots of ideas & info. Thanks a lot everyone! I've definitely concluded that buying a used engine would be a waste of my money. I'm not sure I understand how to determine if the broken valve and/or piston could be replaced without purchasing another head. I suppose the mechanic I use will be able to determine that.

I have a good friend I've known since high school who's hubby is a certified Ford dealership mechanic.... he's always so busy & hates my car tho. He isn't experienced with Geo's other than all the stuff he's done on mine over the past year, but I'll have to see if he can make time to diagnose and maybe fix what’s going on. Actually, everybody rags on my car, but I happen to love my little egg. :wub:

I'll post an update when I have one. First in line is my rack & pinion *sigh*
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Bad Bent
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Facetious Educated Donkey

IMHO, it's really not a good idea to have anyone work on your car that does not like it. :shake

Especially a die hard Ford person working on a Chevy with a Suzuki engine is not a good formula. :-/

Start a new post in the lounge asking for help or look at the Available Metro Mechanics where you have ki4syr - Sparta, North Carolina and a little further north Metroschultz - Virginia Beach, Virginia.

I had my rack and pinion rebuilt by Garo in Florida. That to is a fairly simple install. After the steering column is disconnected with 2 bolts the R&P is held on with 4 bolts and the tie rod ends are hammered off, gently from the bottom. The rest is measurements or a professional alignment. Garo: http://www.merchantcircle.com/business/Garo.Rack.And.Pinion.305-558-1551
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BillHoo
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You might just have a chunk of carbon or something clogging a valve. I'd try this over-the-counter before any major surgery:

Get two bottles of Seafoam from you auto parts shop.

Use one bottle:
- 1/3 in a half tank of gas
- 1/3 in the oil
- 1/3 in the throttle body - pour in and let it sit for 10 -15 minutes. Then start the car and take it ofr a drive on the highway (it'll smoke like the dickens)

Run the engine over the next week or so. when you've gone 200 - 300 miles, get the air filter and oil changed.

Is there a difference? If so, do it again a few hundred miles before your next oil change.
Edited by BillHoo, Feb 18 2011, 01:29 PM.
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93metrochick
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BadBent
 
IMHO, it's really not a good idea to have anyone work on your car that does not like it.

Especially a die hard Ford person working on a Chevy with a Suzuki engine is not a good formula.

Start a new post in the lounge asking for help or look at the Available Metro Mechanics where you have ki4syr - Sparta, North Carolina and a little further north Metroschultz - Virginia Beach, Virginia.

I had my rack and pinion rebuilt by Garo in Florida. That to is a fairly simple install. After the steering column is disconnected with 2 bolts the R&P is held on with 4 bolts and the tie rod ends are hammered off, gently from the bottom. The rest is measurements or a professional alignment. Garo: http://www.merchantcircle.com/business/Garo.Rack.And.Pinion.305-558-1551
I appreciate the concern, but I've known him since high school which has been about 20 years now and I'm very close with him & his wife. He definitly wouldn't attempt anything that he didn't think he could accomplish. Not liking my car wouldn't affect his quality of work either.

However, I haven't had the need for engine work until this issue, so the stuff that he's done in the past year were things like brakes, radiator hoses, thermostat, wheel bearings, lower control rods, switching out my steering column, etc.

I WILL, however, look into the section of the forum you mentioned about Geo experienced mechanics tho. I've been thinking about that myself already, especially if I'm facing a major engine repair like this.

BillHoo
 
You might just have a chunk of carbon or something clogging a valve. I'd try this over-the-counter before any major surgery:

Get two bottles of Seafoam from you auto parts shop.

Use one bottle:
- 1/3 in a half tank of gas
- 1/3 in the oil
- 1/3 in the throttle body - pour in and let it sit for 10 -15 minutes. Then start the car and take it ofr a drive on the highway (it'll smoke like the dickens)

Run the engine over the next week or so. when you've gone 200 - 300 miles, get the air filter and oil changed.

Is there a difference? If so, do it again a few hundred miles before your next oil change.


Thank you very much for this suggestion, I had actually read somewhere on the forum about seafoam and had been meaning to try it soon anyway.

"smoke like the dickens".... for how long? I just want to know what to expect.... should I be alarmed if it smokes the entire 200-300 miles or is this something that is only going to happen initially for the first few miles or so?
Edited by 93metrochick, Feb 19 2011, 10:09 AM.
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mcmancuso
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It pours smoke right after you start it, but stops as soon as it burns out of the cylinders, maybe a minute at most.
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