Compression Issue on Cylinder 5 on friends 100

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2000UZJ

2000UZJ

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I am posting this for a good friend of mine in the Atlanta area. He has a 2004, stock and is driven by his mother, oil changes every 5,000 miles.

He did the timing belt 3 months ago, water pump, belts, tensioners, etc. It ran fine until yesterday when the CEL started blinking. The dealer said that cylinder #5 had 30lbs compression and the others were sitting at 165lbs. He poured 1/2 cup of combustion cleaner into the cylinder and vacuumed it out 45 minutes later. He states the cylinder is firing and the truck is running fine. The dealer wants to put a new engine in and gave him a quote just north of $22,000.

Any ideas? What could cause a cylinder to drop compression so quickly? He stated the sparks and coil packs are firing normally.

He is not a member, but I do think he will be joining soon to get some answers.
 
Paul May of Equipt is the only other truck I've ever heard of a cylinder going, he lost compression on one of his. Similar thing though, truck was running, just running rough a little. I hesitate to say even that because now everyone is going to think their truck running rough is a bad cylinder. But, he had a crap ton of miles on his motor. Can't remember the exact cause or diagnosis, if the sleeve or rings went bad or what.

He put in a reman motor, think it tallied about $6-7k with install at a Toy dealership.

Has he rechecked compression since the cleaner and what was the code it threw?
 
I'm sorry. I got hung up on the $22,000 quote. Really?

On the compression issue, my guess is the timing belt jumped a tooth? That's about the only way to lose compression short of having a catastrophic failure except for a head gasket or a valve seal. You'd have to bend a valve, mess up a seat, etc unless maybe there's enough carbon buildup or ingestion of a foreign object (paper from a torn filter?) to cause a good valve to lose seat.

$22,000? Really? Damn.
 
He has not rechecked the compression since the cleaner. I told him the timing belt may of been off a tooth as well, but wouldn't that be instant? It ran fine for 3 months. His mother doesn't drive it hard at all, so carbon build up may be an issue. I'd hate to tell him to go wind it out on the highway and end up blowing the engine and/or making the issue worse. I'll follow up with him and let him know to have the cylinder re-checked. The dealer said the code was low compression on cylinder 5.

For $22K, he his very close to the price of a diesel swap! Did May ever find out what happened to the cylinder?
 
2000UZJ said:
I am posting this for a good friend of mine in the Atlanta area. He has a 2004, stock and is driven by his mother, oil changes every 5,000 miles.

He did the timing belt 3 months ago, water pump, belts, tensioners, etc. It ran fine until yesterday when the CEL started blinking. The dealer said that cylinder #5 had 30lbs compression and the others were sitting at 165lbs. He poured 1/2 cup of combustion cleaner into the cylinder and vacuumed it out 45 minutes later. He states the cylinder is firing and the truck is running fine. The dealer wants to put a new engine in and gave him a quote just north of $22,000.

Any ideas? What could cause a cylinder to drop compression so quickly? He stated the sparks and coil packs are firing normally.

He is not a member, but I do think he will be joining soon to get some answers.
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the dealer gave HIM, or his MOM a quote of $22K?
 
My guess is stuck rings (carboned up), broken ring lands, or very carbon-laden valves....

Is there any valve train noise?

If no noise, has anyone ran a leak down gauge on that hole to listen for air leakage past an intake or exhaust valve or out the PCV vent?

Yeah, that is some sorry crap from their dealer... That is a fail


IMHO.... If the timing is off, it would run rough or have incorrect compression in multiple holes on that bank of the engine, not just one hole


This might be a good candidate for some water/alcohol cleansing and or a seafoam injestion
 
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I'd definitely do a thorough seafoam treatment via a vacuum hose - repeatedly.
 
bamachem said:
I'm sorry. I got hung up on the $22,000 quote. Really? On the compression issue, my guess is the timing belt jumped a tooth? That's about the only way to lose compression short of having a catastrophic failure except for a head gasket or a valve seal. You'd have to bend a valve, mess up a seat, etc unless maybe there's enough carbon buildup or ingestion of a foreign object (paper from a torn filter?) to cause a good valve to lose seat. $22,000? Really? Damn.
Click to expand...

For 22k I would swap in a diesel :)
 
It's a 2004. Even if low miles it's not even worth $22k. They probably gave a uber-high price like that so she'd just trade it in and they could do her a favor and give her $5k for it and then fix it for a couple hundred bucks and resell for $20k on the lot. Damn stealerships.
 
I recommended getting a few opinions, ACC being one of them. I'm thinking the motor is clogged with deposits and/or carbon.

Would Seafoam help in this instance? Or just a good hard drive to blow the cobwebs out? Any other suggestions? Why could throw a blinking CEL that would be related to low compression? $22,000 seems a bit high.

You can get a fully built twin turn I 2UZ from TTC for around $25K. Assuming you can use your old engine as the core, it may be the same price as the dealer. Not to go off topic, but for the money I'd do this to my 2UZ-FE.

image-3358318048.webp
 
Hate to state the obvious, but why doesn't he just thread in a compression gauge and see for himself?

It could be that the stealer just didn't get #5 threaded in all the way and had a bad reading that they were already expecting to see. So they stopped their diagnosis at that point. Just like what happened to poor Rohitash.
 
OregonLC said:
Hate to state the obvious, but why doesn't he just thread in a compression gauge and see for himself? It could be that the stealer just didn't get #5 threaded in all the way and had a bad reading that they were already expecting to see. So they stopped their diagnosis at that point. Just like what happened to poor Rohitash.
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He may be registering on MUD to post up directly. I'd like to see him get a few different opinions. What would cause low compression? I'm not that well versed in engines, so I'm clueless right now.
 
The next step is a leak down check to see where the compression is going. Head or rings.

The belt being a tooth off has very little to do w compression on a single cylinder.

I did see a 4.0 in a 4-runner w 90k miles loose compression on a single cylinder but the owner decided to trade it in over further dio.
 
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