Over pressurizing coolant system

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Alaska and Oregon
Hello gentlemen,

I dont normally post in this section but I just ran into a fellow in the last few days that is stumped. He is from Switzerland and is making his rounds on the globe doing pictures and videos of wildlife with his 1978 RHD FJ45 pickup (H 6cy diesel.) He is currently in Valdez Alaska right now staying with a co-worker until he can get back on the road.

So here is the problem that he states: The vehicle over pressurizes and spews out radiator fluid when his RPMS are up. I have seen the vehicle do this twice now.

So far he has replaced his head gaskets twice, a new water pump, new thermostat, new engine, checked the head with dye for cracks then had it milled, and he has replaced hoses. The only thing left I can think of is the radiator. He does have a inline coolant heater maybe this is blocking the flow of coolant and causing it to fill the expantion tank for the radiator fluid? any ideas guys.

The other problem is this new engine he just put in puts out alot of black smoke, I am sure this is just some type of an adjustment. Knowing nothing about diesel engines I hope you guys have a better idea than I.

Thanks again guys and hopefully we can get this guy back on the road.

Robert
 
Thats what he thought until he replaced the head gasket twice now and then replaced the engine when that failed.
 
Hello gentlemen,

I dont normally post in this section but I just ran into a fellow in the last few days that is stumped. He is from Switzerland and is making his rounds on the globe doing pictures and videos of wildlife with his 1978 RHD FJ45 pickup (H 6cy diesel.) He is currently in Valdez Alaska right now staying with a co-worker until he can get back on the road.

So here is the problem that he states: The vehicle over pressurizes and spews out radiator fluid when his RPMS are up. I have seen the vehicle do this twice now.

So far he has replaced his head gaskets twice, a new water pump, new thermostat, new engine, checked the head with dye for cracks then had it milled, and he has replaced hoses. The only thing left I can think of is the radiator. He does have a inline coolant heater maybe this is blocking the flow of coolant and causing it to fill the expantion tank for the radiator fluid? any ideas guys.

The other problem is this new engine he just put in puts out alot of black smoke, I am sure this is just some type of an adjustment. Knowing nothing about diesel engines I hope you guys have a better idea than I.

Thanks again guys and hopefully we can get this guy back on the road.

Robert


Seems to me he should check his radiator cap, if it is bad it will do what you describe.
 
He also replaced the cap as well, would a restriction in the radiator cause it to overpressure an fill up the little expantion tank?
 
He also replaced the cap as well, would a restriction in the radiator cause it to overpressure an fill up the little expantion tank?

Yes, because the coolant cannot cool down... because it cannot flow through rad (quickly enough, or at all).

Fix the simple things first, then do the complicated stuff.

Almost any rad that has a few decades on it should get replaced. We often replace rads when doing engine work that may have been related to cooling issues, it's cheap insurance - engine rebuild $5k to $8k, rad ~$400 - $500 - it's a bit of a no-brainer.

~John
 
Black smoke = smoke monster. (sounds like an episode of Lost!)

Smoke = too much fuel, too much fuel = too much heat, too much heat = dead engine.

What engine is in there now? 2H probably?

Find threads in this section about turning the fuel down (probably find it in Turbo threads).

~John
 
He stated he has the "H" diesel engine installed. Its a 1978 right hand drive (RHD) from Africa, he is an electrical engineer and purchased it while on assignment there.
 
My 3B did the same thing once after I did a poor job replacing the head gasket. Does the engine ever overheat? I kinda doubt a radiator blockage severe enough to overflow the overflow wouldn't alo raise engine temps overall.

Solution for me was to redo the HG job, replacing the cheap ass aftermarket HG with a beautiful new OEM multilayer steel HG. Also had the head milled and cleaned the block perfectly. No more bubbles.
 
Thanks for the input, he stated that on the last engine he had a shop profesionally install a new gasket. When that didnt work he did it again and took his time with the same results. Then he purchased a new engine and had the exact same problem. The old block had the head milled as well but still no luck. Thats why I was inclined to think it was a radiator issue or hoses. the engine has not overheated in both cases and the temp guage does work. When he turns off the truck it the guage goes up like normal.

Robert
 
So here is an update, he has taken off the radiator and did a flush on it to make sure there are no restrictions throught it. It seems to be fine so he is going to replace the headgasket one more time to see if thats the problem. This will be his third time and his first time with the second engine.

Robert
 
Personally, Don't just randomly replace parts without verifying that it is defective. Some one correct me if this procedure does not work on diesels vs gas engines. Take it into a emission repair shop, start the engine and when it starts to bubble at the filler neck, put the tip of a 5 gas emissions analyzer near it. If the HC or other readings skyrocket, you have a head gasket that's blown. If not, then its another issue. If there is blockage, then yes, it can overheat and blow head gasket.

Now, as some one else stated, check easy and cheap things first! Once had a idiot shop said my water pump was leaking and that's why it was overheating.

Took it to a pro radiator and muffler shop, they said it was the cap. The spring was broken and it was leaking water on the top of the pump and dripping down. Ohh I was not happy. It caused my head to warp causing the engine to loose antifreeze.
 
If you're really doing the HG, IMO its very worth the money for the OEM gasket, which is a nice multi-layer steel gasket instead of the composite/honeycomb aftermarket jobs.

I have a thread on here somewhere about those combustion gas testers you can get over the counter at auto parts stores - you stick a tube of fluid where the radiator cap went and if it changes color, you've got exhaust in the coolant loop. Works great. You can use the gasser fluid on a diesel too, just takes longer to change colors.
 
There is no MLS OEM gasket available for the H engine. There's no more OEM head gaskets of any type available for the H. It's aftermarket only at this point. The ones that come in the head gasket kit from SOR suck. Really bad. Get one from engineaustralia.com.au. I wish I knew the brand they sell. Much better construction than the SOR ones (or the ones from Roodog's in AU) I had mine in 4 days from Engine Australia via FedEx and shipping wasn't crazy expensive.

I currently have Cometic working on an MLS gasket for the H. They have never seen a design like the Toyota precup where the fire ring extends out under the whole precup. They're trying to come up with a workable solution. I should have CAD drawings sometime this week.
 
BTW, there are two different head gaskets for the H. There's a slight difference near the rear of the head where the oil drains down through the block to the pan. I have a diagram but can't post it at the moment (wrong computer). I can email it if anyone needs it.

I don't know that the Land Cruisers ever used both gasket types. The H was used in a lot of Dyna applications. I think one of the versions may be for them.
 
So here is an update, he has taken off the radiator and did a flush on it to make sure there are no restrictions throught it. It seems to be fine so he is going to replace the headgasket one more time to see if thats the problem. This will be his third time and his first time with the second engine.

Robert

If it is an old radiator it would be better to take the tank off and rod the cores as they are most likely blocked in the bottom of the radiator.
Also check the injection pump setting to see how much it is over fueling.
 
He also replaced the cap as well, would a restriction in the radiator cause it to overpressure an fill up the little expantion tank?

The trick to solving problems is stop making assumptions.
New part doesn't = working part, has the person tested his radiator cap, tested his radiator for hydrocarbons, tested his radiator for hot or cold spots, pressure tested his complete cooling system, tested the thermostat.
A real simple and easy test replace the upper radiator hose with a clear hose run the engine see if bubbles are in the water column also allows a look at water flow, test the radiator while running see if there are cold and hot spots.
If he has a blown head gasket compression gas will be in the water as bubbles.


Jim
 
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So far he has replaced his head gaskets twice, a new water pump, new thermostat, new engine, checked the head with dye for cracks then had it milled, and he has replaced hoses. The only thing left I can think of is the radiator. He does have a inline coolant heater maybe this is blocking the flow of coolant and causing it to fill the expantion tank for the radiator fluid? any ideas guys.

The other problem is this new engine he just put in puts out alot of black smoke, I am sure this is just some type of an adjustment. Knowing nothing about diesel engines I hope you guys have a better idea than I. Robert

One final question, it's stated he replaced his engine with a "new engine" do you mean a new engine, a used engine, a rebuilt engine?
If it is a used engine what was its condition? Does it have a overheating problem unrelated to the first engine like a cracked head?

Jim
 
Be systematic. Determine if there's a leak, poor circulation, or poor heat exchange. Start by pressure testing the cooling system.
 
Quote:
Originally Posted by Alaskan_IB View Post
He also replaced the cap as well, would a restriction in the radiator cause it to overpressure an fill up the little expantion tank?

If the radiator has blockages in the cores the pump is ineffective [even cavitates at times] the restriction causes the water in the head to boil around the exhaust valves and other hot spots in the head as it is not free flowing. The water expands before becoming steam. The same as a thermostat that will not open does.
 

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