Radiator was blown, fixed, but fearing it will happen again. (1 Viewer)

[Mike02]

I have a 1994 LC FJ80. I recently migrated from Minnesota to Oregon. Since I have owned the 80 (aprox. 6 months) there has been a very small/slow coolant leak. I have owned many vehicles with this same issue (no biggy). Anywho it progressively got worse on my journey westward and in Weaverville, CA the radiator blew out. I would also like to note that this was approximately 20 miles after I put in some Radiator "stop leak". I got some local mechanics to pull the radiator, and we found the hole at the bottom of the radiator along the seam. Around this area the radiator was "bulged" indicating to me some pretty high pressure. I had them solder the seam just to get me home (a new radiator from Redding, CA was $560.00) Everything seemed fine, but my check engine light came on for about 20 miles from Weaverville to Grants Pass, OR (probably unrelated). I believe it was the next day when I opened the hood to give everything a once over and noticed a bulging at the top of my radiator!!!!! This bulge was never there!!!!! I have not driven the 80 more than a few blocks since, until I figure out what is going on. My only idea is a blown head gasket, but I checked for bubbles in the radiator and there was none. Any of you Land Cruiser scholars have any ideas????? Thanks - I'm new to the forum (well new to posting, I've been reading the forum since before I got the 80) BTW it has 190,000 miles, locked, 3" OME heavy spring lift, 295x75xR16 BFG AT's, ARB winch bull bar.

Thanks
Mike

 

[Mark W]

Blown head gasket almost certainly. I have seen bad head gaskets in the 1FZ explode radiators. Bubbles in the cooling system are a good seat of the pants quick check, but not seeing them is not the end all of diagnosis.


Mark...

 

[IdahoDoug]

This is not indicative of a blown head gasket. I don't know what you mean by 'bulge', nor what you refer to as a 'seam'. A factory radiator could not bulge along a seam because the only seam is where the plastic top or bottom tank mates with the metal core. Obviously a bulge would mean the plastic would break. Obviously if it was soldered, then it's metal to metal. So, you have a non factory radiator and who knows what you have.

Additionally, as to pressure, the most you could have in the radiator is a measly 14psi - about what you'd see in a child's bike tire. That's because the radiator cap would release the pressure at 14psi. So, internal pressure is not likely the culprit unless this thing is either weak or damaged severely.

So. You have something going on but I don't think you've found the problem yet. I suspect you have an offbrand radiator that's failing for internal structure reasons and if it's distorting (your 'bulging') then my read would be it's very weak and will continue to let you down.

 

[Mark W]

Sorry Doug, but a head gasket failure WILL explode a radiator in an '80. OEM radiators.

Seen it.

Have one here at the shop right now as a matter of fact. The plastic fractures and blows out. The plastic actually stretches before it fails, so this is probably the bulge that he is referring to. As to why the cap does not release the pressure, I can't tell you with 100% confidence, but my guess (95%+ confidence) is that there is simply too much gas, too fast for the cap to vent it.


Mark...

 

['74 UA FJ]

Or the cap has failed in the closed position.

 

[Ebag333]

If you aren't much past Grants Pass, PM me or hit up the JSC forums. We can probably assist.

 

[Cruzer_89]

New HG my friend is what you need...

 

[raydouble]

Test for blown headgasket/cracked head...........
Replace rad cap and thermostat for sure.

 

[Mark W]

I am gonna back of from saying that the problem is definitely a blown headgasket. Because..... no report of the rig running poorly? And I am curious as to exactly where a plastic and AL radiator was soldered?

Kinda confused now


Mark...

 

[Mike02]

The radiator is all metal (brass) The seam I am speaking of is where the bottom of the radiator folds over and meets the radiator coils. this is where it blew out. The bulging that I'm refearing to was at the bottom of the metal radiator at this seam from the inside pushing out. Now I've noticed a bulge from the inside out at the top of the metal (brass) radiator. Just looks like a whole hell of a lot of pressure. I see that the radiator cap is rated for 13 PSI. The cap appears to be fine - not much to it just a spring and rubber "gasket".

 

[Ebag333]

Mike: Where are you located in Oregon?

 

[Mike02]

I am in Grants Pass

 

[Michael Hanson]

Try a new rad. cap and put a vacuum gauge on the the cruiser. MIke

 

[Mike02]

Just bought a new radiator cap. I'll keep an eye on it

 

[Michael Hanson]

Vacuum gauge 5 min. install,20$. Mike

 

[IdahoDoug]

The OEM rads in 80s have plastic top and bottom tanks, and the top tank is often damaged by techs kneeling on it to service things at the rear of the long engine bay. The "exploding" action is a misnomer. Pressure in the cooling system would never exceed 14psi unless the rad cap has rusted on - an extremely rare occurrance as the cap is designed of non rusting materials specifically to avoid this scenario. What happens in the "exploding" events is that water is prevented from boiling by the pressure of the closed system - water's boiling point is raised above its normal 212 degrees. That's how the system works. When the top tank finally fully cracks, pressure in the cooling system drops and the water instantly boils and expands rapidly.

In the case of a HG leaking, combustion gases are entering the cooling system and causing a constant stream of bubbles out the 14psi valve of the rad cap and into the overflow tank. In an extreme case, would there actually be enough combustion pressure to explode the radiator? Yes, but take a look at the radiator cap and compress the 14/13lb spring and you'll see that even a huge HG leak would be handled. Air could literally be whistling out the cap like a teapot on steroids and still the pressure in the cooling system would be less than 14psi. I grant it could happen, but it's my feeling that it's rare and I don't think he's got a problem with his HG yet.

DougM

 

[Mike02]

My radiator must not be OEM, because it is brass at the top and bottom. This "bulge" a convex lump at the top of the radiator that occured from the inside out did occur around a small section that was soldered when we had the radiator out. I'm kind of thinking that where he heated up the radiator with a torch it weakened a little bit (I hope)

 

[Mike02]

CJF (Curtis) came over today to help with the situation (Thank you Curtis). I pulled all the spark plugs and did a compression test. Here are my results. These were the approximate readings that I got on the 4th stroke of the engine:
1 - 180
2 - 180
3 - 180-185
4 - 190-195
5 - 180
6 - 190-200

What do you guys think?
The pictured spark plugs are #2 and #6 (6 on the left 2 on the right)

 

[maybe_a_80...]

first of all, nice lookin' rig!

I hope you can solve the issue, hopefully it is not a blow hedgasket, I do not have enough experience to tell you one way or another.

Depending on the age of your radiator (it sounds like it is not a Toyota OEM unit) and the rest of your cooling system, you may have blockage somewhere in the coolant system.

Might try getting the whole thing flushed. A coolant system baseline (flush, new hoses, etc) is always good PM if you have not done this, mainly for future reference. Problematic coolant system is one of the top reasons older model vehicles break down.

Good luck!

 

[mkguyvr]

Another way you can check for a bad head gasket is to take the suspected cylinder maybe #6 and line it up on the compression stroke, pull the plug on that cylinder and thread in your compression tester, now hook you compressor to the tester line and pressurize the cylinder and let the compressor hold 100 or so psi on it while you remove the radiator cap. If it has a bad head gasket it will push the water level up and out of the radiator. Also look for a milky residue under your oil cap...tell tale sign of a bad head gasket. Good Luck