1986 F250 Possible Head Gasket Issue.. Anything else to check prior to Yanking it out

[Hiball]

Hello Fellow IDI Junkies.. Im fairly recent to the IDI world but did acquire a 86 6.9 F250 Extended Cab, 4x4, C6 Auto with 49K showing on the Clock (PO said it rolled once, Who knows?) I was actually gonna sell this truck and have been driving it around lately and decided to keep it. The Other day I noticed that the Upper Radiator hose was swelled up (engine Running) and was extremely difficult to compress. The 1st that came to mind was Head Gasket, So I shut it down, Let it cool down and grabbed my "Combustion Gas Checking Tool". Started it back up, Waited for things to start circulating and without a doubt It turned the special dye Bright Green when I pumped the bulb, Which per the instructions = combustion gasses. After doing some Research im leaning towards just pulling the Motor to complete the Task and Now im just wondering how far I should take it.. Complete Rebuild? I haven't noticed any tell tale water signs in the oil Cap nor any water/Mixture showing on the Dipstick, I haven't done a oil change (which would probably shed a little light). The Oil pressure gauge has always showed a little low, My plan is to get a compression check of all the Cylinders (already have the Gauge with proper glow plug attachment) and getting a secondary oil pressure reading from the actual Port. Is there anything else I can do that would aid me in determining the Engine Condition or help me make a decision on how far to take the Rebuild? Anything I should do prior to pulling it?

Again im fairly New to the IDI world but have learned quite a bit from past posts, So Please bare with me if im asking redundant or Silly Questions.

Thanks

 

[riotwarrior]

Welcome to OB, the best place for info bar none on these old rides.

Sounds like you have a great understanding of whats going on and short of a compression test or a leakdown test there isn't much more you can do.

Take a gander in the FAQ section and TECH articles and don't forget the Hall of Shame to save your money.

Not sure about a purchase, check here we've likely seen it done it tossed it or loved it.

About pulling the engine hard to say, the comp test will tell lots, if it's only rolled once well then head off in frame though not easy, DON"T ask I just did this and it's worse for me...anyway it is doable for sure!

Again Welcome to OB and post some pics btw

Al

 

[Hiball]

Thanks for the welcome, i suspect ill know more after the compression test, ill post back with the results. On the positive side I'm fortunate that it didnt sell when I had it listed recently, I would have hated to sell it to someone only to find out it had engine issues later.

 

[icanfixall]

Welocome to the forum. The idea of selling a rig that needs work is something most wont do but if you didn't know it needed work its understandable. Pulling the engine is the best way to do head gaskets. Doing an inframe head hasket job alone is a very heavy tuff job. Not something I would tell someone to do. An engine can re removed easier than one things. I do all my work alone and an engine will come out over the radiater support with the hood on the cab. Its a heavy lift up over but its doable. Its much simpler to remove the front clip or at least remove the radiater core support. Then the engine is not lifted so high over the core support. Less of a danger to you and not so high of a lift. Alomst straight out. No matter how you pull the engine. Please remove the oil filter. then you have more room to lift it out. Doing a compression test is a great idea. Just remove all the glow plugs. Then its easy to crank over the engine. Might want to use a charger on the batterys because they may run down on you. A slower cranking cylinder usuallly has a lower reading. 240 lbs is felt rebuild time and 420 to 530 is concidered a great engine. Don't worry about compression testing a warm engine. These engines have an oil squirter up under the pistons for cooling. So oil is on the cylinders and rings when cranking. Oil shot into the cylinders like a gasser is burned as fuel in a diesel. So please don't shoot sany in the cylinders checking the valves and rings. Its not needed. How much you want to do when the heads are off and the engine is out is up to you. I sure would do the oil cooler o rings while it out..

 

[Hiball]

Welocome to the forum. The idea of selling a rig that needs work is something most wont do but if you didn't know it needed work its understandable. Pulling the engine is the best way to do head gaskets. Doing an inframe head hasket job alone is a very heavy tuff job. Not something I would tell someone to do. An engine can re removed easier than one things. I do all my work alone and an engine will come out over the radiater support with the hood on the cab. Its a heavy lift up over but its doable. Its much simpler to remove the front clip or at least remove the radiater core support. Then the engine is not lifted so high over the core support. Less of a danger to you and not so high of a lift. Alomst straight out. No matter how you pull the engine. Please remove the oil filter. then you have more room to lift it out. Doing a compression test is a great idea. Just remove all the glow plugs. Then its easy to crank over the engine. Might want to use a charger on the batterys because they may run down on you. A slower cranking cylinder usuallly has a lower reading. 240 lbs is felt rebuild time and 420 to 530 is concidered a great engine. Don't worry about compression testing a warm engine. These engines have an oil squirter up under the pistons for cooling. So oil is on the cylinders and rings when cranking. Oil shot into the cylinders like a gasser is burned as fuel in a diesel. So please don't shoot sany in the cylinders checking the valves and rings. Its not needed. How much you want to do when the heads are off and the engine is out is up to you. I sure would do the oil cooler o rings while it out..

Thanks for the Advice! I agree trying to sell a vehicle that has problems even the slightest one is Uphill business. I never thought about "Not" doing a dry and Wet compression test, But I can definitely see the reasoning now. Ill try to get around to doing that compression test the 1st part of the week and report back with the Results. Im leaning towards just pulling the engine completely out, Just dont know if I should remove the Core support or just "Up and Over". How much extra work does it entail in removing the support?

Oh and @Riotwarrior.. I spent last night reading up on your recent issues/threads. Good Times... But thanks for the Detailed Explanations, I feel like I learned a lot, Sadly at your expense.

Thanks Again.

 

[icanfixall]

Once all the glow plugs are out crank over the engine. See if any coolant comes out of a plug hole. Be careful because these engines make plenty of cranking air pressure coming out of the hole. Bits of carbon are likely to come out. That really hurts the eyes and face.. Been there too. Looking at the intake manifold you will see the number of that cylinder on the port runner near the manifold to head bolts.

 

[Hiball]

Once all the glow plugs are out crank over the engine. See if any coolant comes out of a plug hole. Be careful because these engines make plenty of cranking air pressure coming out of the hole. Bits of carbon are likely to come out. That really hurts the eyes and face.. Been there too. Looking at the intake manifold you will see the number of that cylinder on the port runner near the manifold to head bolts.

Will Do..

 

[Agnem]

Here is my article on how to do your gaskets in-frame if you want to see what that looks like. http://www.thedieselstop.com/contents/getitems.php3?6.9L Gasket and Turbo Install

 

[Hiball]

Here is my article on how to do your gaskets in-frame if you want to see what that looks like. http://www.thedieselstop.com/contents/getitems.php3?6.9L Gasket and Turbo Install

I actually ran across that Thread and have it bookmarked accordingly, I think im going to let my compression tests dictate whether the motor comes out or stays in for the Job. Ive got the tools/shop to complete the task, with my Job its tough to find the time (Railroader).

Thanks for the write up.

 

[Hiball]

Well I got around to yanking the Glow plug out and getting some Compression Numbers today, I didn't notice any flying Water or see any wet spots in the Galley prior to running the compression test. The initial Number represent the Initial compression Number (1 or 2 cycles) and the 2nd number is where the cylinder topped out.


1. 200, 440
2. 200, 350
3. 200, 450
4. 225, 425
5. 200, 425
6. 220, 425
7. 225, 450
8. 225, 450

Thoughts? Outside of Cylinder #2 being much weaker, I ended up double checking that cylinder and came back with the Same results.

 

[riotwarrior]

Thanks for the Advice! I agree trying to sell a vehicle that has problems even the slightest one is Uphill business. I never thought about "Not" doing a dry and Wet compression test, But I can definitely see the reasoning now. Ill try to get around to doing that compression test the 1st part of the week and report back with the Results. Im leaning towards just pulling the engine completely out, Just dont know if I should remove the Core support or just "Up and Over". How much extra work does it entail in removing the support?

Oh and @Riotwarrior.. I spent last night reading up on your recent issues/threads. Good Times... But thanks for the Detailed Explanations, I feel like I learned a lot, Sadly at your expense.

Thanks Again.

Ya wet test not good plan, that's where leak down comes in

IMHO after doing the heads in-frame as I had started...I'd give very serious consideration to an engine removal instead. Rear most pushrod on passengers side would not come out, and two head bolts on drivers side would not. ROYAL PITA for sure. However now it's all changed

Glad that my experiences can provide insight and helpful information to others. It is not at my expense you read it...it was your time and your life, you can't get those minutes back so it's your expense!

I've been trying to put together good useful tech articles for all to read and share their experiences in as well. However...sometimes people DON"T READ THE RED STATEMENT when I start them Gary!

Well I got around to yanking the Glow plug out and getting some Compression Numbers today, I didn't notice any flying Water or see any wet spots in the Galley prior to running the compression test. The initial Number represent the Initial compression Number (1 or 2 cycles) and the 2nd number is where the cylinder topped out.


1. 200, 440 2. 200, 350

3. 200, 450 4. 225, 425

5. 200, 425 6. 220, 425

7. 225, 450 8. 225, 450


Thoughts? Outside of Cylinder #2 being much weaker, I ended up double checking that cylinder and came back with the Same results.

Ok so looking at this two ways first...75% of highest cylinder minimum is 337.5 lbs so you are above that good

Now the average of 7 cylinders 437.5 lbs and then %75 of that...328 lbs so even that way you are within spec.

You mention combustion gasses in coolant test but did you get a Pffffft when removing rad cap?

Fire engine up from cold, and let run a few minutes then pull cap if get pffft from pressure it's HG for sure, if not could be something else.

Based on your findings I'll go with HG however those comp numbers lead me to think valve or rings, likely valve...

Hope this helps.

BTW, If you choose to remove engine, essentially 12 bolts some hoses some electrical and the entire front clip is off in one piece. Ya full access. IMHO and actually I'll say NOT SO humble this time. I'd not do a rad support only removal ever again. Full clip removal or not at all. Too fiddly and too many small ***** to deal with removing rad support.

Clip removal leave RAD Shroud whole nine yards in even batteris ifn u can lift it with two people I know I did it without bats but with rad n such...

Hope that is of some help and thanks for the PM!

Al

 

[Hiball]

Thanks for the Info.. Ill do some investigating tomorrow on what it takes to remove the Front clip as a whole.

 

[riotwarrior]

I can provide some good info...done lots of clips only way to go IMHO!