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Unread 07-27-2009   #1 (permalink)
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Default 4.6 2v mustang head gasket!

Afternoon all!

I'm looking for a writeup on head gasket replacement for a 2001 gt 2v 4.6 mustang (need to know what i'm up against)!

I have oil mixing with antifreeze in my mustang and i'm more then likely looking at doing a head gasket job this weekend.

As for engine contamination....
If I have antifreeze leaking into oil it isn't very much because i'm not seeing any of the milky oil signs (not on filler cap, dip stick or in oil)! I'm seeing oil in the antifreeze however (just changed coolant and it is alread brown and oily colored)!
I don't think it is rust because I seen oil floating in the drained coolant.

I'm gonna do a compression test to verify gasket but i'm certain that it is the gasket because I see no other way oil would be getting into the coolant! What is a good clyinder reading and variance between cylinders (WET AND DRY)!

Car Backround....
I own it about 4-5 years and I have never used sealant in the cooling system. It also has never run hot nor given me even one problem. The car has nitrous but I never used it (put on by previous owner along with all the other mods). I bought the car with 16,000 miles on it and was and for the most part still is in showroom condition!
As mentioned......
The car is a slightly modded 01 GT (long tube headers, CAI, Direct Port Nitrous system, Prochamber H-Pipe, and Mac Exhaust system). The car has about 70,000 miles on it now. I have no overheating issues or running problems that would point to a blown head gasket. It isn't losing much oil between changes (maybe a pint or less every 3000 miles). The coolant level stays right below the full line and I haven't needed to add any in a year! I noticed the brown colored coolant but didn't think anything of it at the time (about 7 months ago). Just thought it need replaced!!!!

So I quess pending the compression test for right now i'm trying to get all the info on this head gasket job I can, I have never ripped into the 4.6 engine but do have some engine knowledge. Just want to know if it is worth my hassle and if it is over my "head" (no pun intended) or spend the 1,000 or so to get it done at a shop!

Last edited by camon; 07-27-2009 at 01:12 PM. Reason: added info!
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Unread 07-27-2009   #2 (permalink)
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Best advice I can give you is to wait for a final determination until you do a compression test. Have new spark plugs ready (great time to swap them in, given you are doing all the labor anyway, and with the age and mileage, a good idea).

I would hazard a guess that you might just have contaminated coolant and no large head gasket problem per se. There are other additives people put in the coolant inadvertently. Unless you have done all your own oil changes, its possible that a tech spilled something in the coolant (even a few drops of tranny fluid, oil or brake fluid will cause the irridescent coating on the surface of the water). Some coolant additives break down over time and will show up like this as well - something that the prior owner might have done rather than you.

I would also check out the intake manifold, which particularly if you have one of the all-nylon versions is prone to problems. The original owner MIGHT have had this upgrade/repair done as well, and some oil could well have migrated to the coolant at that time.

It would be unusual (though certainly not impossible) for you to have a tiny oil leak that was one way, ie, that never allowed coolant to mix with the oil as well as the reverse. If the car runs well and monitoring the oil shows no contamination, this is a clue.

Has the oil in the coolant re-appeared after flushing out the cooling system and topping up with all new coolant and water?

Finally, if you do elect to do the gasket upgrade, it IS a good bit of work, particularly with the engine in the car. Access is tight up against the firewall, and the exhaust will probably resist you at every turn.

Buy a good manual (Ford has the best, but the Chilton or Haynes are better than nothing) and read through the chapters involved.

I would grade it a 8 on the pita meter, maybe an 8.2.
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Unread 07-27-2009   #3 (permalink)
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I'm breathing a small sigh of relief as I type this (knock on wood)!

I was asking everyone that knew anything about cars as well as my own experience and I too never heard of coolant getting contaminated and not the oil. Brother had a bad head gasket in his Z26 baretta once and that had contamination in both oil and coolant (he drove it like this for a year or better until he junked it, but it was still running, what a knuckle head)!

I also was told by my brother that he last used the drain pan during an oil change he did a few weeks back and never rinsed it out (drained it but didn't rinse it). So this would explain the massive oil contamination I seen when I transfered the coolant to clear bottles (I have an enclosed drain pan).

So now.......
I'm leaning more towards a rad. flush, because I don't see any oil in the fresh coolant (hard to tell because the coolant is so dirty). I also checked compression on all cylinders but 2 (which I couldn't get to without pulling the CAI off). All plugs removed read between 155-160 (dry test) I will check the other 2 this weekend when I have more time. I didn't buy new plugs because I did this about 6 months ago!

So baring any bad readings on hole 3 or 4 (the 2 I couldn't get to) I think I might be safe in the head gasket department (Fingers crossed)!

Thanks for the indepth response tripleblack!

I will update my finding this weekend!
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Unread 07-27-2009   #4 (permalink)
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Good luck. I have a feeling you just need some regular maintenance and you will be good to go.

But your alertness is NOT a bad thing. Sharp eye to see what you saw. Better to be critical than miss a critical warning sign.
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Unread 08-01-2009   #5 (permalink)
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Afternoon all!

Well I got the compression test complete on all cylinders!The only thing I forgot to do and depending on the answer here it may force me to do the test over. I forgot to do the test at WOT!

What will the WOT do for the numbers (raise or lower)?

My findings ***DRY TEST***:
(cranking about 4 cylces for each cylinder)

#1- 160psi
#2- 155psi
#3- 160psi
#4- 160psi
#5- 155psi
#6- 160psi
#7- 145psi
#8- 150psi

Hole 7 is the only one that i'm slightly concerned about, as it is 15psi off (about 10%) from my highest reading holes of 160psi.

Are these decent numbers, and again how will WOT effect these readings?

I also flushed the coolant system with a case of destilled (sp?) water. refilled it with coolant Took the car for a 30 mile cruise left it cool down and the antifreeze looks good (the quick flush I did seems to have cleaned it up)!

Well let me know if I need to go back down to the garage tonight and run this compression test again??????
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Mods: Stock Black Interior With Silver Trim, Mac CAI - Mac Long Tube Headers - Accufab Plenum - Accufab 70mm Throttle Body - Prochamber H-Pipe - MAC Exhaust - 5.0 Short Throw Shifter - NOS Wet Direct-Port Nitrous system (w/2600-6000rpm window switch) - Air/Fuel Gauge and Nitrous Pressure Gauge (A-Pillar mounted).
Future Mods: Supercharger (7-9psi), Roush Kit w/Exhaust
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Unread 08-01-2009   #6 (permalink)
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OK, first off, #7 is just far enough off the rest to trouble me. 15 is about where you start to figure something is wrong. 10 is a warning sign.

Run the test again and verify your results. I'm hoping the bad cylinder is just a fluke. Frankly the 150 in #8 is none to good, either. Anyway, add a capful of motoroil to that suspect piston before you crank it over.

If the number goes up, you probably have worn rings. If it stays the same, the wear is in the valves.

If you had 2 adjacent cylinders with low numbers, it might indicate a blown head gasket between the two cylinders. (7 at 145 and 8 at 150 may be significant). If the head gasket is leaking between the 2 cylinders, you can't get a good compression read on either of them.

Quote:
Originally Posted by camon View Post
Afternoon all!

Well I got the compression test complete on all cylinders!The only thing I forgot to do and depending on the answer here it may force me to do the test over. I forgot to do the test at WOT!

What will the WOT do for the numbers (raise or lower)?

My findings ***DRY TEST***:
(cranking about 4 cylces for each cylinder)

#1- 160psi
#2- 155psi
#3- 160psi
#4- 160psi
#5- 155psi
#6- 160psi
#7- 145psi
#8- 150psi

Hole 7 is the only one that i'm slightly concerned about, as it is 15psi off (about 10%) from my highest reading holes of 160psi.

Are these decent numbers, and again how will WOT effect these readings?

I also flushed the coolant system with a case of destilled (sp?) water. refilled it with coolant Took the car for a 30 mile cruise left it cool down and the antifreeze looks good (the quick flush I did seems to have cleaned it up)!

Well let me know if I need to go back down to the garage tonight and run this compression test again??????
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Unread 08-01-2009   #7 (permalink)
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Well I will go down a little later tonight and re-test them (this time at WOT).

The 145 concerned me aswell alittle bit because all the rest were in the 150-160 range (if I cranked the engine 5 cycles instead of 4 cylinder #7 climbed to 155psi)! My compression gauge isn't one of the best, it counts off in 5psi increments. Much rather have one that counts in 1psi increments!

Thanks for the input!

Let you know results!
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2001 Ford Mustang GT: - 2v 4.6 Liter - 5 Speed (3650 Tremec) - Stock Wheels, Tires and Suspension - Charcoal Leather Interior
Mods: Stock Black Interior With Silver Trim, Mac CAI - Mac Long Tube Headers - Accufab Plenum - Accufab 70mm Throttle Body - Prochamber H-Pipe - MAC Exhaust - 5.0 Short Throw Shifter - NOS Wet Direct-Port Nitrous system (w/2600-6000rpm window switch) - Air/Fuel Gauge and Nitrous Pressure Gauge (A-Pillar mounted).
Future Mods: Supercharger (7-9psi), Roush Kit w/Exhaust
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Unread 08-01-2009   #8 (permalink)
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OK!

My last post I typed the wrong cylinder # it wasn't #7 that was 145psi it was #3 ( hole right under throttle body)!
(Anyway...)

Re-tested....
Started with hole 5 (removed cop and plug) threaded in copression tester held thottle pedal wide open and cranked engine over about 4 cranks (or about 3 sec.) looked at gauge noted reading released pressure and did the hole a second time and noted reading. Re-installed plug and cop and moved on to the next cylinder (testing order: 5,6,7,8 - 1,2,3,4 )!

Results:
Test #1
#4-145psi #8-145psi
#3-140psi #7-145psi
#2-150psi #6-140psi
#1-145psi #5-140psi

Test #2
#4-145psi #8-150psi
#3-145psi #7-150psi
#2-145psi #6-145psi
#1-150psi #5-145psi

I tested each hole twice because it's hard to crank each hole the same (for me anyway). This could explain the reason the 1st and 2nd test values don't match up! I had a hard time counting cranks, and doing it myself from in the car I couldn't watch compression build on the tester needle! I was also surprised that my numbers dropped (I was seeing 160's the first time through). It seemed like I was cranking the same as the first time!

I added oil to the original low pressure hole (#3) and the reading went up slightly to 150 with oil (I thought the pressure should build more then this, but it only went up 5psi)!

Well pending a verdict from here I will leave well enough alone "for now"!

Thanks again...for the input and look foward to hearing thoughts!!
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Mods: Stock Black Interior With Silver Trim, Mac CAI - Mac Long Tube Headers - Accufab Plenum - Accufab 70mm Throttle Body - Prochamber H-Pipe - MAC Exhaust - 5.0 Short Throw Shifter - NOS Wet Direct-Port Nitrous system (w/2600-6000rpm window switch) - Air/Fuel Gauge and Nitrous Pressure Gauge (A-Pillar mounted).
Future Mods: Supercharger (7-9psi), Roush Kit w/Exhaust
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Unread 08-02-2009   #9 (permalink)
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The best method involves removing ALL the plugs simultaneously, of course. For future ref. And 140-160 is a good range to look for in general terms.

I still think you are good to go, particularly without the worrisome results from the compression test.
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Unread 08-02-2009   #10 (permalink)
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Thanks for the thread attention Tripleblack, it was very much appreciated!

I learned alot about testing compression, and will use this info learned in the future. In hind-sight I should've had a second person to crank the engine so I could've monitored the gauge needle to verify strokes. In the future I will!

Well thanks again for the help and have a great day!
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2001 Ford Mustang GT: - 2v 4.6 Liter - 5 Speed (3650 Tremec) - Stock Wheels, Tires and Suspension - Charcoal Leather Interior
Mods: Stock Black Interior With Silver Trim, Mac CAI - Mac Long Tube Headers - Accufab Plenum - Accufab 70mm Throttle Body - Prochamber H-Pipe - MAC Exhaust - 5.0 Short Throw Shifter - NOS Wet Direct-Port Nitrous system (w/2600-6000rpm window switch) - Air/Fuel Gauge and Nitrous Pressure Gauge (A-Pillar mounted).
Future Mods: Supercharger (7-9psi), Roush Kit w/Exhaust
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Unread 08-02-2009   #11 (permalink)
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I think your fine I would not worry with it now just keep an eye on things. it takes a lot to blow a head gasket on these 4.6's
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