Blown head gasket(s) ??

[ragtopfury]

1989 Shelby Dakota 318. Original untouched bottom end with 95k miles. I put a pair of rebuilt heads from Jegs on it because all but 3 exhaust manifold bolts broke off when removing the manifolds to put on a pair of headers. They were cheaper (maybe not after all) than taking the originals to a shop to be refreshed and all broken bolts removed. Typical normal Fel-Pro head gaskets. 9 months later, the radiator is having babies.... She's puking coolant out the overflow bottle. Was not running hot at all, previously - ~180 when hot. As soon as I start it, cold, with the radiator cap off, it's blowing out the radiator.

Did a compression test (cold engine) to see which cylinder is the culprit. All 8 are higher than I expected being between 160-170. No coolant in the oil. Do I need to retest when hot?

Now what I did, for grins and giggles as well as to prove to my son that it will run on just 4 cylinders because he did not believe me.... Put the plugs back in 2, 4, 6, 8.... Fired it up and still puking coolant. He said must be the right side head. So we pulled the even plugs, put the odd side back in and did the same. Same result, not quite as bad. Ghetto, I know, but figured its gotta come apart any how.

 

[dano]

Possible cracked head(s)? Does the exhaust smell like its burning coolant?

 

[middleagecrisis]

I’ve had the same issue on small block Fords because they don’t have as many head bolts and tend to have head gasket failures more often. You’ve got a leaking head gasket into one of your coolant ports. Usually, you see a drop in compression when you do a test, but The issues you’re describing are pointing to the above. You’re going to have to take the heads off regardless. When you do, you can look at the head gasket and I’ll bet you’ll find a breach into a water jacket.

 

[ragtopfury]

Possible cracked head(s)? Does the exhaust smell like its burning coolant?

No odd exhaust smell or steam.

 

[ragtopfury]

...... You’re going to have to take the heads off regardless. When you do, you can look at the head gasket and I’ll bet you’ll find a breach into a water jacket.

Yeah, the disassembly begins tomorrow...

 

[middleagecrisis]

Yeah, the disassembly begins tomorrow...

Please post up some pictures of the head gaskets and what you found.

 

[ragtopfury]

I lied. Disassembly just began this evening. Got one header unbolted.....

 

[middleagecrisis]

I lied. Disassembly just began this evening. Got one header unbolted.....

I hear you! Everyday life takes up way too much of my Duster time nowadays. Keep us posted.

 

[RustyRatRod]

Gonna be kinda funny if it was a stuck open thermostat and the radiator is stopped up.

 

[middleagecrisis]

Gonna be kinda funny if it was a stuck open thermostat and the radiator is stopped up.

Easy enough to check the radiator by running some water in the top and out the bottom before yanking the heads. Coolant has to be drained anyways before yanking the heads. Problem just started after 9 months, so I doubt the radiator clogged overnight. Pukes coolant when cold, so thermostat (open or closed) shouldn't be part of the equation.

 

[RustyRatRod]

Easy enough to check the radiator by running some water in the top and out the bottom before yanking the heads. Coolant has to be drained anyways before yanking the heads. Problem just started after 9 months, so I doubt the radiator clogged overnight. Pukes coolant when cold, so thermostat (open or closed) shouldn't be part of the equation.

Sure it would be. If it's stuck open the water pump is pumping coolant into the radiator all the time, even cold. If the radiator is stopped up, it's gonna puke coolant, since it has nowhere to go. When I first got Vixen, that's exactly what was wrong. Stopped up radiator and stuck open thermostat. With the cap off, when you fired the engine up, coolant went everywhere, because it could not go through the radiator. I'm not saying that's what it is, but I'd sure as hell DIAGNOSE the damn thing, before I ripped the heads off. But WTF do I know? Go for it. It's not my time, trouble or money.

 

[middleagecrisis]

Easy RRR, I was just saying he could physically try running water through the radiator to verify flow. Radiator has to be drained to pull the heads or at least should be. Easy enough at that point to put a bucket underneath the lower hose and run water through the top. If water goes in one side and comes out the other, then the thermostat isn't the problem, because it's puking water when cold.

 

[ragtopfury]

Radiator drained PDQ when I opened the drain. It flows very well.

 

[LO23M8B]

If you want to check the radiator hold your hand over the lower hose barb and fill it up with water, then move your hand. It should come gushing out like no tomorrow and empty itself in a few seconds.

 

[mygasser]

Radiator drained PDQ when I opened the drain. It flows very well.

that won't tell you much as the drain tap's very small. see post 14 above to check rad' flow the right way

 

[ragtopfury]

Runs out the drain with a 10 inch long gush, but will do as mentioned above and see. Heading to Hersheypark for the weekend today, so y'all be patient.... LOL

 

[ragtopfury]

Well guys and girls, I believe I found the issue. Pulled the right side head this morning. Where the needle nose are pointing, it is obvious the head never fully compressed the gasket at the centermost water jackets. Put a straight edge across the head with an LED drop light behind it. Not real easy to get in a pic, but there is light in the center area. Thought ok, let's verify. Used 2 more straight edges and got the same light leakage.
Going to pull the left side and take both to the machine shop.

 

[ragtopfury]

Left side is actually worse....

 

[Newbomb Turk]

Were the heads machined when you put it together?

 

[ragtopfury]

Yes. JEGS black Friday deals last year. Bought the pair already done.

 

[tinman2]

This would be a good time to check the block deck also. I worked on a 360 a couple of years ago with a blown head gasket. The block deck was pulled up at each headbolt hole leaving a .003" dip where the gasket blew out.

I tried to link to the thread but it wasn't showing what I wanted.

 

[ragtopfury]

I did lay the straight edge across the block surface after scraping the gasket off. Seems fine.

 

[mygasser]

Left side is actually worse....

View attachment 1716475514

 

[junkyardhero]

cinder blocks and sandpaper sort you right out on that, machine shops are a ripoff man.

 

[JDMopar]

cinder blocks and sandpaper sort you right on on that, machine shops are a ripoff man.

But only if he has a Ban saw to take care of the pistons...lol