Low cylinder pressure

[DoctorJest]

Okay -- I'm running a '95 4runner, and about six months ago I had the head gasket replaced. Since then, I've come to a new guy to look over the fact that our engine's running rough, and he's told me that one of the six cylinders is running low, at 90psi (I believe) instead of something somewhat higher.

He's talking to me about the options to repair this, but I'm not sure about what I want to do -- we got the 4runner through a dubious sale, and later found it had been crashed, so it's had problems ever since, and in the event of needing to replace the whole engine, I'm thinking it could be more than we can afford to do (we're pretty broke at the moment). Just the repairs I was expecting were going to run $1200, and that's more than I wanted to be swinging. I'm guessing an engine will be three or four times that, give or take, and there'll still be eight hundred bucks left in repairs that are needed elsewhere to get it running smoothly.

So my main question for now is, simply -- can a 4runner last for any length of time with one of its cylinders running low like this? I'm trying to get a feel for how much time I can buy here -- if any at all -- before I'm forced to either shell out for this heavy repair, or to ditch it and look to pick up something else instead.

 

[DoctorJest]

Also -- if the cylinder does need tweaking -- has anyone had any luck with Engine Restorer? I know it'd probably be a temporary thing, but I'm wondering if it might buy me some time so that I can actually get some money together to pay for more serious work later on.

 

[KidVermicious]

How long it'll last depends entirely on why that cylinder has low compression. If the head gasket job was botched, the thing could let go on you at any moment. If it's a bad valve or bad piston ring seal you're more likely to get more time out of it. Either way you're on borrowed time, but you could have your mechanic run a leakdown test and/or block test to give you more info to go on.

Which way you jump depends on how attached you are to the truck (not very, it sounds like) and how much it'd cost you to replace it, vs. the cost of repair. I will say this, if you're reliant on a mechanic then an old old truck is not the vehicle you want to be driving, because it will need maintenance. It'll cost a lot less if you're willing to grab your tools and get dirty.

 

[nevada]

Okay -- I'm running a '95 4runner, and about six months ago I had the head gasket replaced. Since then, I've come to a new guy to look over the fact that our engine's running rough, and he's told me that one of the six cylinders is running low, at 90psi (I believe) instead of something somewhat higher.

He's talking to me about the options to repair this, but I'm not sure about what I want to do -- we got the 4runner through a dubious sale, and later found it had been crashed, so it's had problems ever since, and in the event of needing to replace the whole engine, I'm thinking it could be more than we can afford to do (we're pretty broke at the moment). Just the repairs I was expecting were going to run $1200, and that's more than I wanted to be swinging. I'm guessing an engine will be three or four times that, give or take, and there'll still be eight hundred bucks left in repairs that are needed elsewhere to get it running smoothly.

So my main question for now is, simply -- can a 4runner last for any length of time with one of its cylinders running low like this? I'm trying to get a feel for how much time I can buy here -- if any at all -- before I'm forced to either shell out for this heavy repair, or to ditch it and look to pick up something else instead.

you say it runs rough, does it smooth out at higher rpms?


the fact that its still building compression at all, leads me to think it should be a fairly easy fix. it may be as simple as adjusting the valves.

also, taking into account what kid said above, that engine could run for the rest of the time you own it.

 

[DoctorJest]

you say it runs rough, does it smooth out at higher rpms?

the fact that its still building compression at all, leads me to think it should be a fairly easy fix. it may be as simple as adjusting the valves.

also, taking into account what kid said above, that engine could run for the rest of the time you own it.

Yes, it does smooth out at higher RPMs -- I really only notice it being rough when it's idling at junctions and the like. And after it's been running for a little while, it's noticeably smoother even then.

 

[nevada]

Yes, it does smooth out at higher RPMs -- I really only notice it being rough when it's idling at junctions and the like. And after it's been running for a little while, it's noticeably smoother even then.

as said above, it needs a leak down test done, to see where the compression is going. from there you can determine what it will take to fix.

 

[DoctorJest]

Which way you jump depends on how attached you are to the truck (not very, it sounds like)

Actually, much more than it sounds, I think. I love this car, but I just wasn't sure what I could do about it. I was hoping to buy some more time to save money to get this work done, but I may end up pushing to get it done again now.

For working on it myself, I'd love to, but I don't have the tools or the experience to dig down deep into the engine. That said, I may just start to look into this -- the more often I run into a problem that I can't solve myself, the more annoyed I get by the very idea of that. But I'm also advised that it's better to practice on a car that doesn't matter quite so much, so I may need to acquire some tools and a junk car before I can do that.

 

[KidVermicious]

A brand new long block runs around $2000, give or take. A junkyard motor around $300. Figure in your mechanic's time to install it, and either is a good way to get back on the road quick if your current motor dies.