1986 2.9 need some advice.

[grizz3767]

Hey Everyone! I am looking for a little advice on a 1986 with a 2.9 L . The engine had ran fine then thermostate went out and it overheated. We pulled t-stat and we put in new radiator as the old one was looking well worn. Filled the system Burped it several times and all seemed ok. Now it still wants to overheat. It looks as if the the system is building pressure and dumping coolant out the overflow. Replaced radiator cap and was watching the fluid level you can see the coolant (surge when accelerating) looks like water pump is moving coolant. But we still have overheating issues. I removed thermostat with no avail we still overheat. Any suggestions would be appricieated.


Thanks!

Grizz

[Ranger Dave]

head gasket

[grizz3767]

Thought about Head gasket also so this morning went and rented coolant system pressure checker. System held 18 lbs pressure for 1 hr no problem. No steam from tail pipe, no water in oil. Could head gasket still be possibility? I look at fan clutch when you turn it by hand it has some resistance not free wheeling.

Thanks

Grizz

[tekatlarge]

You probably have a cracked head. If it is cracked it may very well hold 14ls of pressure but the cylinder and head area are under much more pressure than 14lbs.

The early 2.9 heads were famous for cracking exactly like you describe. there real thin in the area between the valves. If it is cracked you stand a better chance with World Products heads.

[Ranger Dave]

it may hold 18lb, but not 150lbs of compression

[grizz3767]

Thanks Guys I appreciate the help.

Grizz

[RClem]

But you said no water in the oil! That is where the water from a cracked 2.9 head goes, in the oil pan. If it is cracked on the piston side of the head, you will get steam out the exhaust, a blown head gasket will also put steam out the exhaust, plus it will run like crap. Pull the plugs and look for one or two that are wet with coolant. Water in the oil may not appear immediately, the only way I have found to tell water in the oil before it starts frothing up is to drain it and let it set. The water will be on top in a few minutes.
On one of the forums I saw a picture of a cracked 2.9 head, I have been lucky enough to not crack one, the write up said they normally crack in the area of the valve spring seats or the rocker arm bosses.
My guess would be that you still have air in the system, I have had Fords that were a real bear to get the air out of.
Try looping a heater hose back to the engine, fill the radiator, put the radiator cap on loose and start it up. Let it run till it is up to temp and watch the looped heater hose, it should jump as the air passes threw it. When the system is up to temp it will spew coolant out of the loose cap until the air is out of the system. You will more than likely have to refill at least once.
If you don't have coolant in the system you can connect a garden hose up like you were going to do a back flush and turn the water on and let the water from the hose push the air out. Be careful with this method, to much pressure on the hose will pop something in the system.
You say you replaced the radiator, was it new or a good used one?
Your problem doesn't sound like a cracked head to me, I think you are fighting an air block in the system. Most of the cracked heads I have seen will push bubbles up that can be seen in the radiator in fill hole.

Ray

[Ranger Dave]

It looks as if the the system is building pressure and dumping coolant out the overflow

sounds like a head gasket to me

[grizz3767]

Ok so i went a decided to give it a shot again. Thinking about what could or couldnt be wrong i decided to pull the codes again and I did find i had blown the engine coolant sensor. So i replaced it and on a whim i replace the clutch fan.. what the heck only money right. I had by passed the thermostat so i put in the 192 degree state that it calls for filled it up and let it idle. I burped the system several times and low and behold the thermostat started to cycle and she started to act like normal. She did push a little coolant into the resevoir however once the thermostat started to cycle it sucked the coolant back into the radiator. By the way the radiator was new however it was a single core radiator. Drove the guy around for a 1/2 hour or so and the only thing it did was run on the hotter side but you could definatly see when the thermostat opened and it would cool down. So it might have had a hell of a air bubble in it. Since i replaced the old dual core radiator with a single core could this plut the 192 degree thermostat contribute to the running on the hot side? I do believe the fan clutch helped but dont think is was the problem.

Thanks again for the discussion! You guys rock.

Grizz

[RClem]

Grizz:
I think all 2.9's came with 2 core radiators. My 86 B2 has a brass 2 core, the only one I have ever seen. Anyone reading this, if you got a brass, that didn't come from an earlier year, post it, all I have seen were aluminum.
Recently I got into a heated discussion on another forum over a problem similar to yours, the fellow having the problem never came back to tell what happened, whether he got it fixed, junked it, or what.
Thank YOU for replying.
Anyway the discussion got into the size of radiators, and (we will call him C, cause I don't remember his handle) had this over heating problem with his 2.9? and was asking advice, one of the members suggested he get a 4 core radiator from an X. That is probably not a bad idea, except it is way thick and putting it in front of a 2.9 is not going to be a simple task, the hoses on the one I have from the 2 core on my B2 won't work on the 4 core, the shroud is all together different and the thickness of the radiator moves the shroud way back against the engine.
These problems aside, another issue that came up that I had never considered, a 4 core holds twice as much coolant as a 2 core, so does that mean it takes twice a much air to cool it or is it not going to be cooled enough as it passes threw the radiator. Honestly, I have no idea. In the 50's threw the 7o's it was common practice to put in a bigger radiator if you had a cooling problem and everything else was in good condition.
So think about that.
I believe your problem with your temp going up and down when the thermostat opens and closes is because of the single core radiator, but don't jump to conclusions, drive it for a few days and watch what happens. You may still have a little air in the system or the thermostat may be too hot, I know that is what is recommended and I run one that hot in mine without a problem, but if you read posts on other forums about the 2.9, the majority of those guys say to run a 180.
As long as it is cooling down and keeps things below the red line, I would stick with what I have for a while and see what it does, winter is here, or at least close, and you probably won't have any problems till the temps start to climb next spring.

Ray

[grizz3767]

Thanks to everyone! I will keep you updated. Luckily I kept the old radiator and will have it boiled out and stick it back in. I will also watch the 190 t-stat I may go to the 180 in spring if it heats up to much but as you said it is coming on winter and i do like the heater warm lol.

Thanks to everyone!

Grizz