Cylinder has 30 psi and mechanic said drive it until it's dead and save for a new car-01 Highlander

He said the motor is going and I’d be throwing money at a dead horse. I appreciate the advice, I’d rather have this than taking my money and still the car dying. I need a good 6 months to save up, I need to drive about 40 miles a day, mainly highway. Is this crazy? How long can I do this? I know no one can give me an exact but maybe someone else is/was in the same boat and can let me know how it went.

It’s impossible to tell how long a car with one really bad cylinder will last. I drove a Chrysler product for one full year on two bad cylinders, but they were more than 30 psi.

Since you probable have a lot of blowby, check the oil frequently and keep topping up. If the valves are bad you will eventually plug up the catalytic converter.

There’s too much information missing.
How many miles are on the vehicle?
What are the other cylinders reading?
How well has the vehicle been maintained?
What, exactly, caused you to have the cylinder compressions read? Exactly what were the symptoms?
Did he venture a guess as to why the compression was so low?

We need something to work with here.

What lead u to this diagnosis?
Engine miss?
Good plugs/spark
Good injectors?
Low compression could be sticky valve or crud on valve face
Or a cruded up ring.
Try a cyl ring cleaning procedure and/or an induction cleaning service

Depending on the condition of the rest of the vehicle and mileage, this is not necessarily certain death. You’d need to fill in the details, as noted above. Then I would want to know where the problem is. If it is a top end problem (valves) then this is not as big a deal to fix up than a bottom end problem (piston / rings). Finding this out comes from a “leak-down” test. In the end, it might be it’s not worth fixing. But that mostly depends on exactly what the issue is and whether or not you’ve often neglected the vehicle.

What engine and how many miles on it?
In most cases, when an engine has a cylinder that is very low on compression (30 in this case) the cause is usually a cylinder head valve problem. Your mechanic should have narrowed this down.

Maybe the problem is tight valve lash due to lack of regular lash inspections. If so, a simple adjustment may cure the problem for a long time or at least long enough to get by for a while.
A tight intake valve once adjusted properly may work fine for years. A tight exhaust valve once adjusted is a toss-up as much could depend upon how tight it is and how long it’s been that way.
Even then, adjusting an exhaust valve may bring the compression up to useable and provide some breathing room in the interim.

I can’t fill in all the details until I pick it up and ask but, this was discovered while getting the spark plugs replaced - they ran a compression test and discovered the low PSI. I asked him to prioritize the problems, we ignored a bunch of ignition codes that were spewed out and focused on the spark plug issues. The other cylinders are fine. This beast has eaten oil since the day I got it. I’m fine at lower speeds but if I go an hour at highway speeds I can go through a quart. He said the plugs were filthy and full of oil. The reason I took it in was rough idle, loss of power with acceleration, jumping around of rpm, hesitation, decline in gas mileage, stalled in a car wash (started right up but concerning), after highway driving for around 15 miles and I wait at the stop light near my home it nearly stalls, i give it gas and all I hear is a clicking and no power - then it kicks in after a few panicked seconds. Overall, it’s been great - I park outside in Minneapolis and it starts up every time. It has more trouble the longer it’s running.

Other info: it has 170000 miles and it’s been maintained but worked hard. MN winters are hard on cars. I am always adding oil so I rarely get that changed (only when it’s in for something else). It’s filthy and has some quirks like the windshield wipers don’t shut off, I have to pull the fuse.

"I am always adding oil so I rarely get that changed "

Youch. Ok. Cross your fingers while you save up for another car and ask how much a scrap yard will give you for it. Or toss it up on craigslist as a “project.” Maybe someone out there who just took out a deer is looking for a roadworthy body to drop their engine into.

It would be nice to know the readings from the other cylinders, but it sounds like he did his job right and the engine is shot.

Sorry. It has all the signs.

I’d try going to a heavier base weight oil to maybe stem some of the excess use, then carry a case around with you and keep driving it. It might just go another two years like this. If the rest of the vehicle is in good shape you can use the time searching out a rebuilt or used engine. Perhaps your mechanic can help with this, and perhaps even give you a ballpark estimate on an engine swap.

And, for future reference, adding oil is not the same as changing oil. Adding means you’re just adding more oil to the existing gump. Changing oil removes the gump and starts fresh.

When an engine consumes oil changing it regularly is even more critical due to the excessive blow-by from worn cylinders.

Keep the oil changed, verify that the PCV system is unrestricted and thank the mechanic for his efforts to save you money.

Considering how much abuse it appears to be getting, I would say your mechanic knows you well. For many, prayer works pretty well. Just going on what you have said, there appears to be enough issues all told to do exactly what he says. Not changing the oil and filter, even with a lot of consumption is not good. If anything, it needs sooner changing. 3 to 5 k at least. Keep your AAA card handy, your cell phone charged and don’t go anywhere some one does know your destination and route, and keep warm blankets and a flare gun (just kidding) in the trunk. It’s a hard cruel world when ( not if) your car breaks down.

Yep another vote for more frequent oil changes. Worn engines under 300K don’t happen very often. Take a look at the current interest rates for new cars and you might just forget about saving up for six months. They are disgustingly low while the economy flops around and money keeps getting printed.

Even though what I am going to say here may create a fire storm; if this was my car it is what I would do to try help the engine. I would use a product called Auto-RX in the engine oil. It is a cleaner that works slowly on cleaning the engine internal parts. Some folks that have used it with your type of problems have claimed some very good results after cleaning the engine with the product. Even if the product doesn’t do much all you will be out is the price for the product. Here is a link to their site.

If you can find some Kreen by Kano Labs, it is supposed to work even better.

My brother had a Ford van in his plumbing fleet that he bought used (well used, I might add) that had the 300 cubic inch 6 cylinder engine for $1500. The last 50,000 miles he drove this van, it didn’t have compression on one of the cylinders. He called the truck his Ford 5. He junked the van when the transmission gave out. I think with careful driving, the OP may easily go another 6 months.

You might as well plan on increased spark plug changes also. I had I think it was carbonized rings on a boat cylander causing low compression, my boat guy used Ring Free PLUS, and got compression back. I am not sure of his procedure, but picked up 5 mph at top end!

I was sort of thinking the opposite of Cougar, but still along the lines of what many call “snake oil.” He’s suggesting trying additives to clean things up. I was thinking of additives to gunk things up. For compression issues, clean-up products can clean and free sticky piston rings so that they seal up better. This helps compression. But if they’re more worn and burned up rather than sticky, the gunk additives (that claim to restore compression) look to help seal up gaps where things are worn out. Often they’re thick and goopy things.

Either kind could help a little - or not. They are mostly for engines that are on their way to scrap yard, though. So that’s why I bring it up.

You really should have that valve lash checked because one cylinder that low and all of the rest described as fine points to a valve issue that could possibly be corrected with an adjustment.

At 170k miles a valve lash issue is entirely possible. Lash should be inspected every 30k miles but that is seldom ever done.


You’re correct about valve lash . . . customers often only consider adjusting valves if they’re noisy

Here’s some of my observations about other things they almost never go for

Brake fluid flush . . . unless something was replaced due to a leak
Change differential fluid . . . unless a leak was repaired
Replace rotten exhaust hangers . . . they wait until the muffler is touching the pavement
replace wiper blades during the summer . . . ever heard of dust and bird crap?
coolant every 5 years . . . they wait until something’s leaking or plugged