Low compression questions and problems

[Ecomike]

I have a seperate detailed diagnostic thread at:

http://www.naxja.org/forum/showthread.php?t=934960&highlight=Taurus

that started as an OBD-II misfire code on V-6 Taurus (my sons). I fixed several problems, bad wires, worn plugs, all the details, extensive details and data, including a busted hose and coolant leak while on the freeway doing 60 mph, and subsequent overheating which are in the old thread.

It has 81 PSI compression on the misfiring cylinder #1,

Ok I need some final opinions please!

Firing sequence is 1-4-2-5-3-6 then back to 1

Compression listed in firing order is:

81 PSI (Cyl 1)

125/120 PSI (Cyl 4)
145/155 PSI (Cyl 2)
150 PSI (Cyl 5)
155 PSI (Cyl 3)
115 PSI (Cyl 6)

Compression difference in firing order is:

+41 psi ( 1 to 4)
+20 psi (4 to 2)
+/-5 psi (2 to 5)
+5 psi (5 to 3)
-40 psi (3 to 6)
-34 psi (6 to 1)

What is curious here is that only Cyl #1 is showing up as misfire now, and cyl 1 to cyl 4 has the largest + pressure difference value, +41 psi difference in cylinder compression. The Haynes says 100 PSI minimum and says no more than 15 psi difference between the highest and lowest cylinders. The highest is Cyl #3 and lowest is Cyl #1, 155 - 81 = 74 psi difference.

Wet and dry compression for 4, 5 & 6 were the same. Compression tests were on a COLD engine, after it sat overnight.

The very first OBD-II codes thrown were Cyl #'s 1, 2 and 6 before I replaced the plugs and wires. Cyl 1 & 2 had bad boots on the end of the plug wires, cyl 1 & 6 have low compression, but are not dead. I think I had a single Cyl #5 misfire before replacing the wires and plugs, and after replacing the plug wires the only misfire I got, about 20 in row was, is now Cyl #1.

So here is my question(s). Since I have no antifreeze leaks yet, and thus no antifreeze signs of a head gasket leak, the oil and antifreeze are normal, and no gas bubbles in the coolant overflow bottle, etc, and I still have 81 PSI in cyl #1, what if I pull the valve covers and re-torque the head bolts, then run some heavy duty block sealer through the coolant system to reseal any "trace" head gasket leaks, then just in case I have some cylinder/piston ring wear in the low compression cylinders I could add some Restore to the oil to bring the cylinder compression back up some. Any one think this has a chance in hell of working, if so how long might it last? I realize if it's a tiny valve leak non of these would work, but what are the chances of the valve resealing itself within a few hours of run time on the freeway with the new plugs and wires and repeated resetting of the OBD-II code? In other words how bad is 81 PSI? I could run it and retest it after an hour or two run time?

At this pint, I have no way of knowing for sure if the low compression on #1, 81 PSI is due to head warpage, head gasket beggining to leak, cylinder or piston ring wear, or even more insidious something like piston rings lining up temporarily, a temporary or permanent valve sealing problem, or some of several of these!

Since it is an overhead valve engine , should I pull the valve covers next and inspect the rockers and valve springs?

The last note of data is that the cleanest new spark plug was in Cyl #1, still looked brand new, but since the computer keeps turning off the injector and spark for #1, I am not sure that means anything. The highest compression cylinders showed just a trace of carbon just below the threads on the steel area. No carbon on three of the other plugs including #1.

Keep in mind that there were several problems at the same time, battery died, a few days later the radiator hose blew, so it is difficult to blame the #1 low compression on just the blown radiator hose (age) and the overheating it caused. If plug number 1 was not firing due to the bad plug wire boot being rotted ( I discovered the boots on the plugs on #1 and #2 were rotten while trying to solve the engine misfire problem), it could have washed the oil off of the piston rings and worn the cylinder wall in a very short time. But there is no sign of oil on the old or the new Cyl #1 spark plug, or any other spark plugs for that matter.

In fact it is surprising how clean the used spark plugs were after at least 20,000 miles on an engine with possibly 198,000 miles on it. Unfortunately I do not know if this is the original engine, but it does not act like a worn engine as far as oil consumption is concerned.

Or am I hasta. I has 198,000 miles on the odo. My son bought it 20,000 miles ago. It's been a relaible low cost car up to now.

Thanks for the help people!

 

[xjcody]

In my opinion you're!!!1. Get rid of the ford, and get a jeep, preferablly a xj if you already don't have one. Sounds like the engine needs at least a rebuild, with all those miles and compression readings. Why waste more money on a car that will surely break sometime in the near future(ie: transmission?). I say cut your losses and start fresh on a different car. Best of luck.

 

[darjevon]

Sounds like you really need to just bite the bullet and pull the heads...

 

[comancheon33]

What year of taurus is it? Since you said it had spark plug boots I am guessing you have the 3.0 DOHC motor. What I have ran into on that engine is the valves will start to basically warpor tulip out. When that happens the doesn't always seal in the head. A valve does spin a little and well as go up and down. The valve will tulip then seal sometimes and sometimes not. Considering the engine you have I would one of two things. Find a junkyard motor with less miles or cut your losses. HTH

 

[McQue]

It may be time to move on with a rebuild....I would try the engine top oil to see if it brings back compression at this point...you don't have too much to lose trying it...
I would NOT use the block sealer in the coolant system, since you are not seeing any coolant loss or coolant in the oil... I say that because everything I have ever heard about them is they usually don't work, and when they do, it is usually short term, or it causes other problems in your radiator and water pump, etc...

Sounds like you are learning a lot about this motor and kind of enjoying it...maybe a rebuild won't be that much of a pain...but if you do rebuild it, you have to wonder how long the tranny is gonna keep going... I had 4 different Ford Taurus company cars, approx 2.5 years in duration each, and lost the tranny in 3 of them before 60,000 miles.

McQue

 

[Ecomike]

What year of taurus is it? Since you said it had spark plug boots I am guessing you have the 3.0 DOHC motor. What I have ran into on that engine is the valves will start to basically warpor tulip out. When that happens the doesn't always seal in the head. A valve does spin a little and well as go up and down. The valve will tulip then seal sometimes and sometimes not. Considering the engine you have I would one of two things. Find a junkyard motor with less miles or cut your losses. HTH

It is a 1996 OHV 3.0 L.

It should be pretty easy, relatively speaking, to pull the heads. For all I know it is a newly rebuild engine that got overheated and nearly lost the head gasket, thus not a completely lost head gasket yet, but starting to give way perhaps.


McQue,

If it is the head gasket going I was wondering if retorquing the heads and adding some of the old style fiber and silicate packages to the new formula antifreeze might reseal and strenghten the head gasket and keep it from failing ( All I would need to do is pull the valve covers to retorque the head bolts, right?) it might be one of those rare occasions where its just the right stuff and early enough for it to work, but if it is just coincidence (the overheating from a worn out radiator hose, and if it is worn out valves on their way out, then the heads need work or replacement anyway. I have not done a head job before, but I have no doubt I can do it, just don't want to do any unnecessary work and time is short so I can't afford to redo it a second time.

I have read in the haynes manual that valve springs can be replaced with out pulling the heads, so I am planning to maybe pull the valve covers and take look see there next.

To XJCODY, answer:

I already have 4 XJ's. One is scheduled for believe it or not, a new head gasket, 89 Renix with less than 120,000 miles, go figure! Head gasket is bad between two cylinders, #4 & 5..

So does this sound like it could be worn rings / cylinders at all based on the spark plugs having no oil fouling at all after 20,000 miles and no oil on the new plugs after 3 hrs of continuous running? Any chance of that based on the data? Or does it have to be either valves, or head gasket or maybe even both? Only oil consumption has been right after oil changes in the first 500 to 1000 miles. After toping off the oil at 1000 miles we have seen no oil consumption. It passed the Texas Emission nazi's tests as 5-90 calls them with flying colors only 8 weeks ago.

Has anyone here ever had any luck with block / head gasket sealer???? If so how long did it last and how bad was it before you used the sealer???

For what ever it is worth, I have had extreemly good luck over the last 30 years with several radiator sealants, i.e. coolant additives that seal small trace radiator leaks, especially the fiber based ones. Of course the pressure in a radiator is not as high as the combustion chamber, but there are similarities.

McQue,

What did you mean by "engine top oil"? Did you mean "Restore". From what I have read Restore is a micro coloidal suspension of copper/silver/lead alloy that plates out on and into small scatchs and worn areas in the cylinders. I have heard from several people who used it on oil burners with low compression and they stopped burning oil and the compression leveled out and increased on the bad cylinders. But it does not work on valve problems, head problems or head gasket problems.

So does the 96 Ford Taurus, 3.0 OHV also have a bad reputation?, other than being a ford that is?

So McQue, are you rough on transmissions or do Fords just no like you? LOL? Surprizingly I have never had a ford transmission die on me (yet), but I went through 14 chrysler transmissions on 2 chrysler / dodge vehicles over 10 years time.:rattle:

 

[McQue]

Yes, I was thinking along the lines of a product like RESTORE....not sure what chemical fix is out there to help valve problems...have to do a little research on that...I am not big on "chemical fixes" for heavy duty mechanical devices... cleansers? sure...body work? sure...lubricants? sure...

But after more thought on the situation, your theory on block sealant has merit because you are addressing the problem early on... people that I know that have tried sealants with little or no success, tried them late in the process...had obvious leak/head problems that should have been addressed earlier, and I guess that the latest chemical technology is quite advanced... look at NASA...it uses many chemicals...
As far as retorqueing the head....go for it...it will only cost you some sweat equity, and even though you are busy, sleep is really overrated!

I gotta tell you that those Ford Taurus company car transmissions that failed on me were not pushed hard...I never abused any of my vehicles, except an old Honda motorcycle I rode back in the mid-70's and that baby never failed...gave it to my cousin and it's still running as far as I know!

Good luck with the next steps that you choose...

McQue

 

[Ecomike]

The only one I think of for the valves is Seafoam, if there is carbon or varnish, sludge holding a valve from sealing completely the seafoam might do the trick, clean it so it can reseal. Marvel mystery oil might help to if it is a sticking valve.

Do you recall the years on those company ford taurus transmissions? Were you the only driver?

I do know that many transmissions get cooked because they do have coolers up front. I learned that lesson with my second car.

 

[McQue]

IIIRC they were 89, 92, 94...I even had a Crown Vic tranny torque converter bite the dust on me....

 

[Ecomike]

Well I got a few things done last night. I drained the oil, put in one large can of the additive called "Restore" plus "Marvel Mystery Oil", 1 quart, and topped it off with Chevron 10W30. Then I added two of the brown one inch diameter solid fiber leak sealing pellets to the antifreeze (crushed them first), plus a bottle of Prestone medium duty head gasket sealer, the one that is compatible with antifreeze, it is black with small black pellets in it, not the heavy duty one that takes draining and flushing and installation with just water followed by draining, flushing....etc, then I started the engine and sprayed an entire bottle of carburator cleaner into the air intake via the vent line that goes to the engine oil filler cap vent. Then I ran it for another 10 minutes at various speeds in park, then cleared the OBD-II misfire code.

Drove it and idled it for about 45 minutes, got all the OBD-II monitors to reset while driving it, drove it and idled it with all accessories running for about 25 minutes after getting all OBD-II monitors reset (relearn procedure for the computer was completed according to the scanner), and in all that time I did not get a single engine OBD-II error code or misfire!

SNAKE OIL ROCKS!!!!!!:scared::worship:

I still plan further work including compression tests follow ups, and more Carb cleaner plus Seafoam treatment, but for now I must say even I am impressed with the results.

 

[McQue]

Thats great news! ...Hopefully it turns out to be a long term fix, and gives you another 25K miles or more!...If it does, after using all those chemicals, were gonna start calling you CHEMMIKE, instead of ECOMIKE...(only kiddin)

TGIF...have a great weekend and Holiday season

McQue

 

[Ecomike]

Thats great news! ...Hopefully it turns out to be a long term fix, and gives you another 25K miles or more!...If it does, after using all those chemicals, were gonna start calling you CHEMMIKE, instead of ECOMIKE...(only kiddin)

TGIF...have a great weekend and Holiday season

McQue

Not a bad idea, actually I am a chemical engineer, I chose Ecomike because my company name is EcoShield Environmental, for ecological and economic chemistry and equipment solutuions to environmental cleaning problems.

Anyway, back on topic, I ran it for another 20 minutes this morning, and another 30 minutes this evening, so far with NO engine trouble light flashing or other problems. At one point I walked away and left it idling, when I got back I thought it had died as it was running so quitely and smoothly. I actually had to look at the engine rpm gauge to confirm the engine was still running!

 

[JJacobs]

I don't see a lot of head gasket failures on the 3.0's. But on the Taurus 3.8 which has a similar gasket, the gasket will actually crumble away behind the steel fire ring around the cylinder. Assuming your HG is actually on the way out, this would explain the radiator hose blowing out. Additionally the snake oil treatments you've added do nothing to support the fire ring in the head gasket, so more problems could well be in your near future.

 

[Ecomike]

I don't see a lot of head gasket failures on the 3.0's. But on the Taurus 3.8 which has a similar gasket, the gasket will actually crumble away behind the steel fire ring around the cylinder. Assuming your HG is actually on the way out, this would explain the radiator hose blowing out. Additionally the snake oil treatments you've added do nothing to support the fire ring in the head gasket, so more problems could well be in your near future.

Interesting, I have heard from several others at the Ford Taurus web site that say THEY have frequently replaced head gaskets on 3.0 OHV fords in the Taurus, they being mechanics.

In this case the radiator hose the blow out can be blaimed on a rotton spot on the heater hose that T's off the lower radiator hose. It had been a slow leak for months that we found too late. There never was any gas bubbling out of the coolant visible in the closed system bottle with the cap off.

Actually if there is a head gasket leak between the combustion chamber or the oil ports, and the coolant side, the fibers from the additives and silicates in the coolant will reform good gasket material and reseal it if the head gasket is not completely blown out there yet, and it will reseal the leak if it is very small. It will do nothing for other head gasket leaks like oil to combustion chamber, or directly between adjacent cylinders, or from the combustion chamber to a manifold or to the atmosphere. All depends on where the head gasket is leaking.

In this case I got an early warning from the OBD-II computer before the head gasket was completely blown, if it was blown or going out. Still could have been low compression from dirty valves (carburator cleaner may have dislodged some carbon on the seal area?) or sticking valves, MMO might have cleaned it, or some kind of odd cylider wear or sticking rings issue that MMO and or Restore fixed. Hell it could have been a little bit of all of these!

It is interesting to hear that you have seen few 3.0 HG failures while others have reported the opposite. Gives me some hope for this engine.

 

[JJacobs]

Well... my fingers aren't exactly on the pulse of all the Tauri that come through the doors. I have done a couple sets of 3.8 HG's, but most of that work goes elsewhere in the shop as I mostly do trans and undercar. I haven't really seen the engine techs doing them, though; maybe they're not bringing the failed 3.0's into the dealer.

Old 3.8's on the other hand are notorious for bad HG's, a lot of techs put their kids through school on those motors. I've seen a couple of those (that still ran) where the fire ring had broken and fallen partially into the cylinder, leaving a nice shiny spot on the piston.

If it is a head gasket failure, keep in mind those motors ( 3.0 or 3.8)aren't very robust in the bottom end. It doesn't take much coolant in the oil to wipe out the bearings.

 

[Ecomike]

I've seen a couple of those (that still ran) where the fire ring had broken and fallen partially into the cylinder, leaving a nice shiny spot on the piston.

Thats a scary thought! :shiver:

If it is a head gasket failure, keep in mind those motors ( 3.0 or 3.8)aren't very robust in the bottom end. It doesn't take much coolant in the oil to wipe out the bearings.

I will keep that in mind. We drained the oil for the additive feed and there was no sign of sludge or water or antifreeze in it, yet. I have been checking it and the coolant every 30 minutes of engine run time.

In your experience what is the typical life expectancy of the valves on the 3.0?
Since he has three cylinders that still have full compression, I am leary of jumping to any conclusions as to what might be worn out, for all I know it could have gotten new heads 40,000 miles ago, before he bought it.

 

[Ecomike]

Got some hard compression data today! But first, I put about 3 hrs of run time on the engine since adding the Ecomike snake oil mix. First hour, no misfire codes, halfway into second hour got a misfire Cyl #1. Note that I ran engine for about 30 to 45 minutes once a day for several days, only a few short local trips. I cleared the misfire code and restarted it the next day. In the 3 hours I got only 3 misfire codes, all in the last 1.5 hours, last 2 days, and only while idling in gear, forward, for at least 2 minutes at idle. No misfires in park at idle or at 1500 to 3500 rpm. Also noted the misfire was not continuous, and started as a pending misfire only, that only showed up on the scanner, not the check engine light. Took nearly five minutes to go from a pending to a confirmed misfire code with the service engine light on.

I got to thinking that if the Restore or carburator cleaner, or gasket sealer was working, it might be raising all the cylinders compression at the same rate and thus might still have enough cyl to cyl compression difference to throw the misfire code, so I checked the compression!

Cyl #1 went from 81 psi to 115 psi, an increase of 35 psi
Cyl #4 went from 125 psi to 140 psi, an increase of 15 psi
Cyl # 5 went from 150 psi to 155 psi, an increase of 5 psi
Cyl #6 went from 115 psi to 135 psi, an increase of 20 psi

Almost forgot, 2 things, I ran a second can of carburator cleaner through it after the first misfire, and 1 hour of run time before the latest compression tests. And the spark plugs looked noticably dirty than before with some loose black carbon around the outer steel, ground area. Cyl 1 had a thin black carbon layer on the ceramic electrode insulator, which was a change from before, perhaps from the rich operation of the last, recent can of carburator cleaner. #1 insulator on spark plug had been immaculately clean the first 3 hours, now it is the dirtiest plug, not fauled but just a thin light coat of black carbon on the white insulator.

Personally I am encouraged by the data, inspite of a few occasional misfire codes.

 

[Ecomike]

Update. This beast has been on the road since my last post. Only change has been one oil change last week, about 5000 miles on it since the last post, and the idiot light went out and stayed off for several weeks during and after a long 600 mile highway drive last month. But city traffic, and idling at stop lights trigered the code and idiot light again last week.

 

[Ecomike]

More good news, we cleared the last CEL missfire #1 code, drove it on the freeway long enough for the OBD-II to reset all the sensors, and took in for the annual emissions sticker. IT passed!!!!!! :clap::clap:

arty:

SNAKE OIL ROCKS!!!!!!

 

[Ecomike]

Well the last 4 weeks of December 2008, the rough idle came back, worse than before, and the CEL misfire Cyl 1 came back and stayed. So we pulled the heads over the Christmas holidays. Machine shop found hairline cracks in both heads. So we replaced the heads. Found some pitted spots here and there in the cylinder walls of the #3 cylinder near the top, suspect there may have been more lower down in other cylinders which might explain why the Restore helped out. Head gasket was OK. The rockers and tappets looked brand new, so someone had done a prior engine job before he bought the beast.

The worst head crack was at the valve seat area. The oil seal and valve guide on Cyl #1 finally gave out and fouled the #1 spark plug and cylinder. In summary, he got 20,000 miles out of it before we finally changed the heads.