Yota_Stomper

Hey Guys,

I need some help here. I got a 98 Taco 2.7L 4 banger 165K miles.

Truck had lost gas mileage and power for quite some time. Over the last
few months I noticed it was running a little rough. Check engine light comes on, occasionally it would blink.

The night before I was scheduled to drop it off at the shop I noticed it was leaking oil... I had not done that b4... turns out it's leaking from the Valve cover... That sucks, but I hoped for the best.

I take it to my mechanic who tells me one of the cylinders is shot.. only has about 60 psi in cylinder #3, the others around 140-160 I don't remember exactly. He tells me he thinks the valve is burned but didn't take it apart cuz he wanted me to give him the go ahead first.

So he tells me that he needs to take the head off and have it machined and basically redo the top end... it's gonna run $2200 bucks!!!

This probably sounds like a rip off, but I live in Hawaii where everything is super expensive. But even still that sounds super high... probably replace an engine for about that.

So, I tell him don't bother, I don't have the cash and even if I did I'm not sure I want to sink that much cash into a 15 year old truck with 165K.

Now I love my truck... but I don't want to redo the top end just to have the bottom end fail in the next 10-20k miles from the increased compression. my understanding is the 3rzfe have a super strong bottom end.. but for that price I figure I would run it till the engine blows then just replace the whole engine.

So Not really sure what to do I decided to check the truck myself.
I just need to let you guys know that I've done a little work on my trucks over the years, but never done any real engine work. I don't consider myself a mechanic by any stretch of the imagination... but I want to do what I can to get my baby running right. So, I bought a can ODB scan tool and a compression tester.

this is what I got.


I ran the compression check but being a complete noob, I did it cold.
cylinder #1 is only at 50psi..... 2,3 and 4 are all at 175 psi.

Again, being a noob I didn't do a wet test on the low cylinder. My coolant, and oil look fine. Seems as though the #1 valve is leaking not #3.. but it may be burned? take a look at the plugs.



Does that look like a burned plug / valve at #1?

OK... so my question is... How screwed am I? What do guys think is going on here?

#1 is $2200 reasonable (in the ball park) for parts and labor for a top end.

#2 should I go with a new top end? or just run it till it blows and get a new engine.

#3 Does anyone think it would help to do the doing the Seafoam, Marvel Mystery Oil, water steam clean treatment that Texas Ace suggests here https://www.yotatech.com/forums/f2/s...y-work-243376/

I've already decided that I'm gonna do that treatment cuz I got nothing to loose at this point... but for any of you familiar with that treatment... Could one of you point out the correct vaccum line to use for the treatment?
here is a pic of my engine compartment.


Thanks to everyone for their help.

rokblok

iTrader: (1)

I had my entire 3rz rebuilt for about that. Granted, it was re-using the valves and springs, but machine work, and high priced LCE performance master rebuild kit was less than $2200. Seems a bit high, even for Hawaii.

It's possible to hear combustion explosion with oil filler cap off if its a burnt valve, or maybe even hear just compression trying to get past the burnt valve. Maybe you could get a small probe camera a go in through spark plug hole and inspect? Just throwing some ideas out.

Texas_Ace

With compression that low in #1 sadly I think you have a problem a little more serious then Seafoam is gonna fix. Your mechanic sounds reasonable that a burnt valve or messed up piston are the most likely causes.

The spark plug does indicate that you are getting some oil into the cylinder so it could be the piston/rings although generally stuck rings will still have more compression then that.

I think you are on the right track, run the full treatment as you don't have anything to loose. See what happens. After check the compression again the same way you did before and see if anything improved.

You could run a leakdown test to get a better idea where the problem lies.

On the mainland I would never spend that kind of money fixing an engine with an unknown problem. Not when you can get a whole replacement engine for half that or less. Not sure what the engine prices are out there though.

Price them out and see what you can find. You could replace the engine yourself with the help of a friend and a weekend. It is not that hard, just takes some elbow grease. I would prefer a good condition OEM Toyota engine over a rebuilt engine. Thats just me though.

Yota_Stomper

Wow. thanks for the quick responses.

Hey TA.. could you point out which vacuum line I'm supposed to use... I really don't
know my ass from a carburetor.

when I saw that comp. test at 50 psi I pretty much figured I'm screwed... but I still wanna give it a try.
Surprisingly, it doesn't run or sound THAT bad... just lost some power and a rough idle.

I seriously doubt I could change out an engine... even if I had a cherry picker and a friend (unless that friend was a mechanic)... but is a leak down test something I could do... or is that best left to the shop?

B-Fake

^X2. This is something your mechanic should have done. The symptoms you're describing do sound like a burnt out valve, but the only way to know for sure is a leak down test or pull the head. I've tone a couple valve jobs and they're not that hard to do, you just have to make sure you seat the valves good.

And yeah, $2200 sounds pretty steep.

Texas_Ace

For the seafoam my first pick would be one of those 3 small hoses on top of the throttle body. I bet that they don't all pull vacuum so just figure out which one does and use that.

J2F42C

Since I have the 5vz, I cannot speculate on the time it takes to break down your engine due to the chain. I would think though that your mechanic should charge you no more than $1200.

Yota_Stomper

Well... I've done the treatment TA suggested.

Fuel additives, seafoam, MMO etc. did the water treatment, with the vacuum hose.
seafoam in the oil, intake, etc.

Let it sit over night after the 2nd sea foam treatment. Gonna take it in to work today, then do another treatment tonight... repeat the process tomorrow, tuesday.. then check the compression, the day after (wednesday).

Rides rougher now... problem seems worse.. but I expect that's because the treatment has done a number on the plugs... so no surprise there.

QUESTION:

on Wed. should I do the oil change, filter, new spark plugs b4 I recheck the compression... or does it matter?

Texas_Ace

If you already did the water treatment I would not drive it that long before changing the oil. The seafoam/MMO are ok for extended periods in the oil but the water is not good. Some WILL get into the oil after treatment.

I would change the oil sooner rather then later. Honestly I have found there is only so much these treatments can do in a short time frame. Over the longer time frame that can do more but there comes a point of diminishing returns short term.

I would change the oil tonight after the treatment and then call it good until the next oil change. Put the MMO and even seafoam into the oil and change the oil in ~1000 miles. You can use cheap rotellaT from walmart to cut oil costs. Stick with a good mobile 1 filter for amid 90's Ford turas V6 though.

After the oil change go drive it hard for a little bit and then run another compression test and see what the numbers say.

This is a last ditch effort for cylinder #1. You will be VERY lucky if it helps it much as a more serious problem is more likely sadly.

Yota_Stomper

OK... Changed the Oil... New filter for a 95 V6 Ford Taurus installed too. I put in synthetic 3 qts GTX 10-40, 1 qt Mobile 1 10-40 and 1 qt. MMO. Will run that for a month or so and change again.

I bought the Denso platinum spark plugs for a 98 taco... but he said they aren't OEM?
does it matter ... are they gapped differently?

and when I got the spark plugs I saw this Fiberlock stuff and bought it.


Anyone ever tried this? does this stuff actually work... could this really stop the leak I got in cylinder #1. It says it can. But I put this stuff in the Radiator?
If I put this in the radiator how does it seal a leak in the cylinder?

If anyone has tried the fiberlock please share your experience with it. I suppose it's worth a try anyways... under $40 if it works even as a temp. fix that'd be great.

Texas_Ace

Depends on the densos you got. You want the dual electrode plugs, I paid $17 for mine on ebay IIRC.

DO NOT use that stuff, that is how you kill an engine real fast. It will gum up and clog the entire engine and cause all sorts of problems. That is only for the last ditch effort when you know you are pulling the engine and don't care what happens to it anymore.

Plus that will only fix a busted head gasket or cracked block which is most likely not your problem anyways.

rworegon

^x2 Return that stuff and get your $$ back!!

Robb235

Don't use that stuff. Like others have said before, that's if you have a blown head gasket. I used something similar, came in a green bottle. I think it was called Nano.... something or other, can't remember. Used it to fix a failed lower intake manifold gasket on a Chevy 3100 V6 (this engine is notorious for these failing). I forgot to take out my thermostat, so that stuff caused it to stay stuck open. It worked though. The engine didn't leak any more coolant into the oil for several years, up until I sold the car. But like mentioned before, this won't help your problem of low compression on one cylinder.

Yota_Stomper

Hey guys,

Well the plugs that my mechanic put in a while ago were the K16R-U... (not twin tip)

I just put in the denso PK-16TT. I don't know what dual electrodes are.. but these were only $3 a piece... the iridiums were about 8 bucks a piece.
EDIT: just saw a pic of dual electode plug... these are definitely NOT dual electrode.

At any rate. I won't add the Fiberlock to the radiator at this point... because I'm still not exactly sure what's going on. My mechanic said he did a wet test and it did NOT improve compression. I will recheck the compression later today and also do a wet test and let you guys know the result.

What I don't understand is.. if only the valve is bad... why does the whole cylinder head need to be machined and re-done?

Also.. I have pretty good leak in the valve cover gasket. Is that related? if so how?

thanks again for all the help.

Yota_Stomper

It says it would also fix a leaking cylinder... which 'may' be my problem... .but if the cylinder is leaking at the valve I'm not sure how that stuff would help.

Texas_Ace

It lies, if you put it int he radiator the only way it can improve anything is if there is a leak in the cooling system which is either a bad head gasket or cracked block. The cooling system never comes in contact with any other leak points of the cylinder.

If the valve is bad then the head has to come off and the proper thing to do is machine it before putting it back together. Yo also generally want to do all the valves and rebuild the whole head while it is off unless you know what caused the problem because chances are that another valve will have a problem before long if you don't.

Basically, with how cheap replacement engines are, there is not much reason to pull apart an engine with an unknown problem and go hunting for a fix IMO. Better off replacing the whole thing.

It is really not that hard to do yourself. The hardest part is getting the transmission off the engine but you can also pull them together.

I would run a leakdown test and see if that can narrow down where the issue is.

Yota_Stomper

thank you! that was the answer I was looking for. I kept thinking... how the hell does it get from the radiator to the cylinder?

Expletive deleted

not out here I'm afriad.

see my first comment

your confidence in my abilities in appreciated... however I'm less optimistic.

This seems to be the best course of action. How much should something like that cost?

My mechanic was already bothered that I decided not to have him fix it and he charged me $100 for hooking up the ODB scan tool and doing a compression test. I don't want him to charge me a fortune for something he should have already done.

which leads me to todays results. first the good news. cylinders 2-4 tested at 175psi before treatment...now 2-3 are at 195-200psi and #4 is at 205 psi.

That's pretty awesome... which is what makes this so heartbreaking. I've got an amazing engine that runs... fine frankly... but because of one crappy valve I need a whole new engine!?!? or 2 grand worth or repairs
#1 went from 40-45 before treatment to 55psi today.

So... I did a wet test on cylinder #1 and it went up to 80 psi.
So here's my question is a jump from 55 to 80 psi significant?

My mechanic said that when he did a wet test that is did NOT go up. I'm guessing it's not, which means it's either head gasket or valve. Seeing as my oil doesn't have coolant in it, that makes it valve which is what my mechanic said.

Haynes manual says that it could also be leaking past the valves:
1. burned valve seats and/or faces (my mechanic said it may be a burned valve)
2. warped, cracked or bent valves.

BIG question here for me is... Is it possible to just replace a bad valve seat or bad valve face???

Texas_Ace

The leakdown test should not cost much, you can do it yourself if you can find a tester to rent/borrow (craigslist maybe?).

You can also use a compression tester to get some of the same results. You use the adapter for the compression tester and hook it up to an air compressor. You then set the cylinder to TDC on the compression stoke and slowly increase the pressure.

Then listen to see where the air is leaking out. If you hear it mainly coming out of the oil cap then you can figure a piston/bottom end issue.

If you hear it mainly in the intake manifold or exhaust then you can figure a top end/valve problem.

The test can be inconsistent but sometimes it gives a clear answer.

Glad to hear that the other cylinders improved, about what I would expect from the treatment.

The improvement on #1 doesn't sound like it is the rings and it is something more serious. Valve is the most likely cause unless you are burning oil.

You could just fix the valve that is the problem but you will not know the exact problem until you pull it apart. It could be a big issue or a simple one.

When doing a valve job you really want to get the head fully rebuilt in most cases. Just fixing the issue valve can often lead to another issue popping up shortly after putting it back together.

You could do the head yourself to save a LOT of money. Time and a torque wrench is all you really need. Pull the head yourself and see what the problem is. If you want the get the head rebuilt take it to the machine shop directly and have them do the work. Then just reinstall it.

Up to you but it is not that hard. only real concerns are keeping everything clean and properly torquing the head bolts in the proper order. A friend and a weekend should be more then enough time to pull it and the same to reinstall it if your first time.

Yota_Stomper

Well I'm burning and leaking oil... not leaking a lot... but My oil was full Monday, today (wed). it's 1/2 quart down, so I must be burning oil. What does that mean?

Well I think that's what I may have to do.. I'd rather buy a torque wrench than get exploited by a mechanic.

Sadly, I don't have any friends out here that'd work on my truck with me (or even know how)... and I've never done it before. Isn't there some rebuild kit that I should buy, gaskets, etc. and I don't know where to get the head machined either. Guess I'll have to ask around.

Looks like I know what project I'll be working on over my christmas break

Texas_Ace

If you are burning oil then that tends to point to a bottom end issue vs a valve. A valve seal could cause you to burn oil and could also indirectly cause valve issues but kinda odd for a single valve seal to go bad and the rest to be ok.

Does it smoke at all? Smoke at startup? During revving?

The unknown means that you will be more or less guessing at the problem and could end up pulling the head only to find the bottom end to be the issue and thus wasted a lot of time.

To get an idea on how to do the head work the haynes manual is a good place to start. Or even better download the BGB for your truck and read through the head removal process as that is what I would follow.

That will give you a pretty good idea. The only other issue is rust, if bolts are rusted that can make things a fair amount harder depending on how bad they are rusted. That is mostly the exhaust manifold though.