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2002 H6 - no compression!

21931 Views 59 Replies 11 Participants Last post by  Novablue
Hey guys. I'm hoping you can help me out. I have a 2002 LL Bean with the H6 engine. Went to start it this morning and it just cranked over fast, no start. If you've ever heard an engine trying to start with a broken timing belt, that is what it sounds like. I verified fuel, then spark and both are good. Plugged in my compression tester to the RH middle cylinder and I get zero compression. I don't even want to bother checking the other cylinders because they are such a PITA to get to and I'm fairly certain they all have zero compression also. So what the heck happened here?!? It has about 160k on it and car was running great last night.

My next thought is to pull the timing cover and start checking it out. I'm guessing I have a broken timing chain or stripped timing cog.

Does anyone know where I can find a guide on pulling the cover? I assume I just need to pull the radiator and then I can get at everything?
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I'm wondering if for certain you're getting good sealing of the compression gauge...maybe there is compression the tester just isn't seating fully?

If you remove the valve covers that gives you more clearance to access the plug holes.
I have spark plugs removed from cyl 3, 4, and 2. I performed the cylinder leak down test on the three cylinders with very poor results. 80% leak is standard when I know the valves are be open, when the valves are supposed to close, the needle may jump to 75% leak. Its hard to tell, but I think the air is coming out the exhaust.

I triple checked my crank/cam timing. Its spot on. Triangles all point straight up. It looks just like picture 95 on page 29 of this guide.

What are the chances it jumped timing, bent the exhaust valves, then jumped back in perfect timing? I'm out of ideas. What do I do next? If I pull a valve cover will I be able to tell if a valve is not closing all the way?

Here is a picture in effort to share my misery.
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If a valve isn't closing all the way the clearance should be fairly high.

Looking at the valves with someone cranking the engine might show any abnormalities.

Have to say this is a weird one, I have heard of lost compression from a leaking injector, but not all 6...
Got me brainstorming on this one. 4 things necessary for and engine to operate: Fuel, Air, Fire and Compression. So a review.

You are sure the compression tester is working properly, so no compression on any cylinders. None.

You have spark. Spark means the crank turns otherwise you wouldn't have a signal for TDC to the computer. This is good. The crank is in one piece.

You have fuel. Pump works.

Do you smell raw fuel when the engine is turned over? Yes means the injectors are firing. No means the injectors are not firing. The computer uses the CMP, cam sensor, to fire the injectors.

The gears are rotating? All of them? Are the cams turning with the gears? I know it seems like an dumb question, but I've seen some weird things occur in an engine in the going on 26 years I've been building/repairing.

Air is heard in the exhaust during the leakdown test. Exhaust valves are open. Possibilities are seized lifters holding the valves open, which would also mean bent valves, maybe damaged pistons if the valves are full open. Depends on the force of the impact. Given the amount of sludge/carbon on the front of the engine from the photo, it is a possibility. It would be a fluke that enough lifters seized on shut down to cause a total loss of compression, but nothing is really impossible. It will only need 6 valves unseated to cause all cylinders to lose compression. Lifters could have been seized on start up and that's where the damage occurred. The lifters don't have to be seized now, just may have been a factor when the failure occurred. They don't even have to be seized at the same degree. The head covers will have to be removed to check the valves for open/closed at proper position in relation to the cams.

And you are sure of the cam positions when the leak down was tested on all the cylinders?

I know it may look like a chore, but you are most of the way there. Remove the engine. It can be done in less than an hour's time from where you are now and will make it easier to work with in tracking down the issue. If you rebuild or replace, you will be removing it anyway. And its looking like that's where you are headed.

A full rebuild on one of these can run $3k, parts and machine shop to do it completely. JDM Engine Depot is showing one EZ30D available for $1k. The other option is a salvage motor unless LockMedic has one lying around he can let loose.
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I have seen exactly zero inside covers, but I think cardoc's observation about varnish/gum w'ever is interesting - seems quite dark or thick to me.

Is there something that could have been aspirated that would clog valves? intake parts or filter material?

was there some kinda oil pressure loss causing valves to seize?

has the car ever taken a hit to the oil pan?
Thank you to everybody contributing to the conversation. I really appreciate your experience and ideas.

A quick review
Fuel - I don't have a pressure tester so I did a volume check. It's pumping plenty of fuel. The spark plugs were also wet with fuel. I'm certain.
Spark - I have a spark tester and verified spark on cyl #3 while my wife cranked the engine over.
Compression - Zero confirmed by compression test on cylinder 3 and 4. Major compression leaks confirmed by cyl leak down test on cylinder 1,2,3,4. I'm certain the cam positions were good. I even rotated the crank by hand 720� deg while doing the test to make sure. The needle doesn't go better than 75% on any. When the valves should be closed, I feel air coming from the tailpipe. I haven't checked cylinder 5 and 6. They are hard to get at, and if the other 4 don't work, what is the point?

Some history on the car.
My parents bought it new and had very little problems with it. The oil was changed every 5k miles and they did primarily highway driving. I bought it 2.5 years ago at 108k miles and continued with the 5k oil change interval. After every oil change, I notice the sound of lifters loudly clanging for the first few seconds until oil pressure builds. According to my Dad, it did that after his oil changes from the get-go. Lately, I would pull the fuel pump fuse and crank the engine until the oil light goes off to prime it after oil changes. About 2 years ago, I noticed a small puff of black smoke from the tailpipe at cold start up in the morning. The oil puffs have grown bigger lately but always at cold start up and they never last. After a few seconds the engine runs normal. It burns about a quart of oil every 4k miles.

Interesting enough, this failure happened at cold start up.
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Have you checked to see that the chain actually moves properly when you crank the engine? Broken chain is still my top suspect.

The oil change thing you described sounds interesting. Could be a failing pump or sludge.

I agree with Cardoc (he is the greater expert than me anyway ;) ), you are headed for a new engine. While I believe what you are saying it sounds unbelievable. :confused:

It's worth pulling it out the rest of the way just to make sure at this point.
how many total miles now? Some folks say the valves need adjustment at around 200K - though I can't see that being a primary issue here.

any carbon build-up on the plugs?

oil use seems too good to blame a PCV valve for gumming things up.

kinda feels like low oil pressure/ or oil that is foamy going to the heads but, all I got are wild ideas.
White smoke is water/coolant. Blue smoke is oil. Black smoke is fuel.

Oil deposits on the valves, which accumulates over time due to crankcase venting into the intake, can get to a point where the valves can't seat properly. This is why you should run a can of sea foam through the induction at least once a year to dissolve the build up. It's also a good reason to use high quality oil.

The type of build up that is seen on the front of the block is usually what i see when going high mileage between oil changes with conventional oil or the use of high carbon oils such as Castrol.

The black smoke was an indication of an issue coming up. Given what was posted, this engine is due for a rebuild or recycling.
After every oil change, I notice the sound of lifters loudly clanging for the first few seconds until oil pressure builds.
I never get this on my 03, but i do partly pre-fill the filter with new oil. (can't fill it completely, but maybe by 1/3 or so of it's volume)
On a pushrod engine, something like can be caused by a broken camshaft, but how can it happen here? Cardoc, what's your method of dispensing SeaFoam into intake? Or are you using a kit with a straw? Also, does electronic throttle require any extra steps, given that you can't move it by hand?
I got the valve cover and off. 2 of the bottom screws were very loose and it was leaking oil from there. Was hoping to see a gap between the cam and lifter when off the lobe but that is not the case. At least now I can see the camshaft working. It verifies my same results. Working on cylinder #1, I can now see exactly when the valves should be closed. When #1 is at TDC and all the timing marks align, I send air into the cylinder and the air just pours out the exhaust. I have the O2 sensor removed and the tailpipe plugged with rags and it pours out the O2 sensor hole. My exhaust valves are not closing. I have no other choice but to remove the cylinder head for further inspection.

I'm going to pick up an engine hoist tonight and I took the day off work tomorrow. Try to stop me if you think I'm crazy, but please have a good logical reason. I know this is a strange one.

I found a used engine at nearby salvage yard but anything reasonably priced has over 100k miles on it. Tell me about these JDM engines if anybody has any personal experience. I used one about 12 years ago on a mitsubishi eclipse. It came nice and clean but I remember I had to swap the intake and a ton of other parts due to the difference in emission requirements. Maybe it's not like that anymore? Shipping cost it probably big too.
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On a pushrod engine, something like can be caused by a broken camshaft, but how can it happen here? Cardoc, what's your method of dispensing SeaFoam into intake? Or are you using a kit with a straw? Also, does electronic throttle require any extra steps, given that you can't move it by hand?
You can run a small hose from within the sea foam can to a vacuum port and control the suction into the engine with a clamping device. It works best if you use a centrally located vacuum port or the brake booster hose. Let the engine run at 1200 - 1500 rpm until the bottle is empty then put everything back in place and drive it, getting to higher RPM and then letting off to increase engine vacuum to pull all the residual through and blow it out.

As for the electronic throttle, it is a highly polished aluminum so you must use a solvent safe for electronic T body and a soft bristle brush to remove the carbon build up.

As for the JDM engines, I am running one now with the supercharger and no issues. It came with all the accessories and I only swapped the AC compressor as it was different and lengthened the vacuum hose for the brake booster so it would reach the opposite side of the intake where the port is located for right hand drive cars. Total cost with shipping was 1142.
. . . My exhaust valves are not closing.

. . . .Try to stop me if you think I'm crazy, . . .
Not at all.

It is a strange one indeed, especially if there was no sign of malfunction when the car was last driven. I'm sure I'm not alone in hoping you will be able to identify exactly what's happening (okay, so far at least one exhaust valve isn't closing), and why.
This compression things a mystery! Any chance someone took it out for a UN-authorized midnight ride? Very odd; Good when parked then this overnight. :gasp:

As for the JDM engines,~~~ Total cost with shipping was 1142.
That's a good price! Almost cheaper than having a dealer change your spark plugs.....

I got the engine out. Took me all day and I'm exhausted. Had trouble getting to the lower bell-housing bolts but finally got it. When I separated it from the trans, the torque converter came with it a bit and some fluid leaked out. I just pushed it back in the transmission. Do you think I damaged anything in there? Is there seal behind the torque converter I should replace?

I was hoping to get a cylinder head off today but its going to have to wait. I still need to remove the intake, timing chain, then another 50 or so timing cover bolts.

What am I going to see when I remove the cylinder head? Bent valve, burned seat, hole in valve? My biggest fear is it is perfectly normal and I'm completely crazy!!!!

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Phew! Way to go, and good luck! I'm sure there will be a clear issue once you get in there.
"That's a good price! Almost cheaper than having a dealer change your spark plugs....."

:29: Sometimes true. Of course the engine is in Jersey, so delivery may take a little extra time. I think the trucking is almost caught back up.

It's still seems like a possibility that the lifters stuck when it was shut down and then the damage was done on start up. Could also be a lot of carbon just causing poor seating of the valves.
The cylinder head is off. No bent valves, no holes anywhere. At first I was all upset because nothing was obvious and this is just so strange. But then I took a closer look. LOTS of carbon build up on cylinder and around valve and valve seat.

This appears to be the carbon build up that was holding the exhaust valve open!!! Really??? Will that hold the valve open!?!?

I should also mention that when I drove it the night before, I didn't go far, just moved it in the garage. Then when started the next day, it got another dose of oil and carbon from the bad valve seals. So I guess that was enough???

What do you guys think? Did I figure it out, or did I take apart my wife's car for nothing!?!?!?
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No, you didn't. It's easier to do this work with the engine out. Less hassle and tension.

While you have it apart for the valve job, you may want to consider the condition of the lifters, cams, new bearings is a given and whether you want to do that water pump/chain assembly. At minimum you should replace the guides and tensioners.

This is a good example of why you should use a cleaner in the fuel, intake and quality oils. And don't go a long time between oil changes. If this wasn't a Subaru, it would be trashed.
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