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Blowing coolant out the overflow tank. Head gasket or block??

S

simone0414

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Truck has had a small coolant leak for a few months now. Towed the camper last weekend & she was overheating quite bad. So I pulled the rad & cleaned it up & she is running cooler but now it is blowing coolant out the overflow on the overflow tank. I had my rad cap pressure tested & it failed so I put a new one on but it is still doing it. Under normal driving it doesn't seem to do it now but I towed my camper & it is still doing it under load. Upper rad hose it hard on cold start as well. Oil level is not rising & I see no white smoke. When it does it I lose about 4 litres of coolant in a matter of a few miles of driving.

Is this enough info to determine if it is head gasket or block?

I have read on the other site of some stuff you can dump in that will seal headgasket & craked block leaks. Thermgasket & steel seal. Anyone have any experince with either or any other additive good or bad?

I realize that fixing the problem properly is the best solution but I am trying to find a temp fix for now.
 
The only way you are going to be able to tell what is going on is to yank the heads. Some people may prefer to pull the one side that is leaking and just replace one gasket, -I would not recommend doing that, -I'd do both.

As far as snake-oil sealing products go, -don't waste your time or money.

There is one exception to that though, and that would be the coolant tabs at the chevy store. they do work for small pesky leaks, but nothing as major as a head gasket.

It could be a gasket, it could be a cracked head, or worse, a cracked block. It is most likely a gasket, but the only way to find out is to pull the heads (they gotta come off anyway).

My .02
 
Missy says

yank the engine and get it apart.

To try and do it in the truck is a eal PITA

The likelyhood that the 1 or 2 cylinder has blown to water are great.

There is also a high probability that the block could be erroded at the fire ring on either of the front two cylinders.

Pressure cold is an indicator of a coolant breach to cylinder pressure for sure..
The other very possible issue with a 99 could be a UPPER CYLINDER CRACK on #8 cylinder.

These can and do occur at around 8 Oclock when viewing from the RH side of the engine.

The cracks will run radially around the cylinder about 1 inch from the top deck.

With a cracked cylinder its basically game over. Sleaving one of these is not a great plan.


If the gaskets are still sound and the cylinder is ok the heads can and do crack between the valves as well as from a the exhaust seats out onto the fire deck.

A cracked head is an easy fix, just replace the set and go again.

Doing the heads on these suckers in the engine bay can be done but is a real PITA.

While its down and if the issues are simple, this would be a fine time to check and or replace bearings, rings and such. Rear main seal and other things like soft plugs.

When one head gasket is gone the other is usually soon to follow.

The miles shown in your sig suggests thatn this girl has seen her day in the sun.
 
Thanks for everyones comments. I don't put much faith in the snake oil stuff either but for the cost of it I bought some of the coolant tabs & put them into tonight. If they will work how long should it take? It is pretty much instant or do you have to drive for a while to let it circualte?

Missy your scarying me with some of your comments.:eek: Is there a way to tell if it is a cracked block or head/gasket without pulling everything apart?

Also I am pretty handy & do most repairs myself but have never done head gaskets before. I have read it is pretty straight forward but is alot of work. Is there a how-to on here to help me out? One with pictures would be great.
 
2x MGW (again).
I Don't reccomend a temp fix with additives; they CAN harm otherwise good parts around the bad ones, ie the block, radiator, stick up the t-stat etc. The tabs may not help at all.

Nice sig on the vegoil conv. All the money you save on diesel buys you a new set of head gaskets, if you're lucky.
Bite the bullet and yank the engine, and heads. It's amazing how many details can be bettered while its out, especially with high miles on it.
 
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Thanks Dave. The veg is working really well. Very happy with it. Yes it has saved me alot of money. Putting that money into truck repairs wasn't part of the plan though.:mad2: Oh well. Is what is I guess. No sense in crying about it. Time to get my hands dirty.
 
I would just yank the heads and look for cracks in the bores etc. Have the heads checked by a competent machine shop and if ok, slap it back together.

The main webs are known for cracking but it seems to be a hit or miss situation.

As for snake oils, if you want to do the job on the side of the road in the middle of nowhere and ruin your hols, try the stuff, :mad2: :eek:
 
Actually I don't believe in cure alls in a can either but In a bind the GM tabs work pretty damn good ON A COOLANT LEAK. You have a compression leak. My advice on a limited budget, Find a used motor and drop it in other wise do as MGW says.
Ie: Burning water, gm tabs will work and could easily outlast the motor
your problem, may solve it for a day or a week but probably won't and if it does it will blow out soon.
 
Ok. A friend of mine is a mechanic at a local stealer. Works for Dodge but has worked for GM in the past. He has worked on gassers & diesels but has no experince with the 6.5. Anyway told him my problem & he agrees it could be a head gasket but I also told him that I had the rad out a few days ago to clean it as my truck was running hot when towing. My problem started pretty much right after that. He asked me if I had bled it when I filled her back up. I did what I thought I was supposed to do. I filled the rad up with coolant. Started the truck up, opended the bleeder screw & once coolant came out I tightned it down & topped up the rad. I thought I got it all out but maybe not. He said air could cause my problem. He also said bad t-stat could as well. I didn't change them when I did the rad. I know I should have. My bad. Looking for more opinions on these two possible causes. He is going to bring a coolant pressure tester & a tester to check for exahust gasses in the coolant tommorow. That should give me a better idea of what's going on.

I'm still expecting & planning for the worst but crossing my fingers.
 
You really in most cases don't have to bleed them. I hate to be the one to say it but graspin at straws. Best you can hope for here is a bad headgasket. Good Luck.
 
High mile 6.5's that all of a sudden start blowin coolant usually have a failed head gasket.

Cyls #'s 1 and 2 (front R and L) are the usual suspects.

98- 2000 blocks will crack #8 cylinders at times.

Rip the heads off and have a peek. I just abhore working over the fender on these so I just yank them so I can get up close and intimate.

Good luck and keep us posted

Missy
 
Well you guys were right:iagree: My mechanic buddy brought home one of those coolant testers where you put in some blue liquid in it, suck some coolant up into it & see if it changes color. Blue is good, green is baaaad. Green it is.:mad2: My straw grasping has come to an abrupt end.

She's not burning it & none in oil by visual check.

Any way looking for a good how to on how to change this bugger. My buddy is going to print me off a complete how to from GM for me but anything anyone else can contribute will be great.

I am going to do both heads & have them checked. Have asked around to people who would know & they all suggested the same place so that's where they are going. Have been told that these guys are the best in the province & are highly recomended so I am confident they know what they are doing. Using Felpro gaskets & new head bolts. Hopefully I am covering my bases here.
I have priced gaskets & head bolts locally & the cost is going to be $400 for that. That's for a top end gasket kit, head gaskets & bolts. Does anyone know where I can find them any cheaper that could be shipped to Canada in a few days??

This will be my first time doing this so any tips/suggestions is greatly appriciated.

All this is assuming that the block is not cracked. If so I will have to cross that bridge when I come to it.

I do have a couple questions

Does the IP have to come off or just the lines?

Will I need heat? I have none so I can take the heads out with the manifolds on them & take them somewhere to be seperated?

How heavy are the heads? Will I be able to lift them out or should have a hoist? I don't know where I will get one if needed but will think of something.

Where do I find torque specs & sequences for putting her back together.

I will take pictures & post when I get her apart so you guys can see what's happened.
 
IP stays on the truck. Just the lines and injectors. I have done 6.2 headgaskets without even pulling the injectors. Heads are as heavy as you would expect them to be. I did them by myself. You would be surprised . My manifold bolts on my 2000 looked pretty ugly and they all came out. Someone here should have Torque specs. Put new glows in to but make sure that is your problem before you spend money on parts and the block is toast.
It's not that bad to do. Turbo makes for a bit of a pain but out of all the diesels out there 6.5 is probably the easiest to do.
 
As said, injector lines not the IP. To get the turbo manifold off, remove the passenger side fender liner, its all 13mm headed bolts, you also need to remove the battery and battery tray, and one small 1/4 trim bolt front right if facing the control arm. This gives total access to the turbo manifold, just remove the brace and oil feed line up top, remove the crossover pipe then go thru the wheel wheel, remove the 15mm nuts for the glow plug wire protectors, remove wiring, undo the drain back hose then all the 15mm bolts and lift the whole turbo/manifold assembly from the top, CAKE. :thumbsup:
 
turbovanman said:
As said, injector lines not the IP. To get the turbo manifold off, remove the passenger side fender liner, its all 13mm headed bolts, you also need to remove the battery and battery tray, and one small 1/4 trim bolt front right if facing the control arm. This gives total access to the turbo manifold, just remove the brace and oil feed line up top, remove the crossover pipe then go thru the wheel wheel, remove the 15mm nuts for the glow plug wire protectors, remove wiring, undo the drain back hose then all the 15mm bolts and lift the whole turbo/manifold assembly from the top, CAKE. :thumbsup:
Click to expand...

Forgot that. Can do it without pulling fender but for the 15 mins it takes I agree, way easier.
 
Keep it coming guys. I can't tell you how much I appriciate your help. No way could I do this without it.

So I don't have to pull the injectors? Glows?? The machine shop can still work on the heads that way? I don't have a injector socket but could probably find one if necessary? How do you take the lines off the IP & injectors? Is it as simple as putting a wrench on & turning?
 
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