I finally have the time to work on my Jeep. New water pump and radiator hoses are going in today/tomorrow. I have purified water and Blue Devil flushing additive in the radiator now. Temps are soaring in the 90s.

But first, I want to bring your attention to this: http://www.go.jeep-xj.info/HowtoWaterpump.htm

The author says that the problem with our jeep engines overheating and boiling over is that the coolant doesn't flow fast enough through the motor, so it begins to simmer and boil by the time it gets to the radiator. That makes perfect sense to me. His solution is to install a high flow water pump and high flow thermostat and thermostat housing.

But then he says a 2-row radiator allows the fluid to flow TOO fast and he uses a single row radiator. He also says he had to add a radiator restrictor plate! If I'm following his logic correctly, his claim is that using a high flow water pump and a low flow radiator keeps the coolant pressure inside the engine a little higher. The higher the pressure the more heat it takes to get the water to boil. I guess if you had a low(er) flow water pump but high flow radiator then the pressure of the coolant inside the engine could be too low. Well I have a 2-row radiator (which the author calls a high flow radiator) and a stock water pump that I'm about to install... I guess I'll find out if what he says is true or not.

...

Why not switch to a higher pressure radiator cap?

 

Oh, I forgot to mention that I used the "block tester" again (but drained about half a gallon of coolant/water first) to check for combustion leaks in the coolant. The test succesffuly came up negative. Not a bad head gasket!

 

Seriously considering getting a higher pressure radiator cap after reading this: http://www.tuneruniversity.com/blog/...-radiator-cap/

It won't affect the temperature of the water at all, but it will allow it to get hotter before it boils over. Just another layer of defense against overheating.

On the other hand, I don't want to put any more stress on the plastic radiator reservoirs...

 

Hold on a minute. You report a negative reading on the block test, great. Did you pour a sample of non used fluid into a shot glass and the used fluid into a second shot glass? Then hold them up together in front of a light source. The difference can be subtle but a very small head gasket leak will cause the issues you are stating.

Your jeep looks fairly stock unless I've missed something? A small lift and tires nothing crazy. The stock equipment should be entirely adequate to handle all resonable environments without overheating. If it's not, there is still a failure somewhere. After coming up to temp while driving stop the truck pop the hood and gradually open the throttle to about 3k rpm if you have a friend to watch the tach. Your mechanical fan should be deafening. It should be uncomfortably loud. Gratuitously loud if you will. Do not assume your mechanical fan is good.

 

Unless i missed it, have you replaced the fan clutch?

 

Yea he said down low in his 1st post that he had replaced it. Sounds as if it got real hot. I'd suggest he verifies there's no exhaust gases in the coolant and sends an oil sample away for analysis. Both are cheap to do.

 

YOU JUST HAD TO GO AND RUIN MY DAY DIDN'T YOU

Here I am, just sitting here minding my own business, thinking how nice it is knowing that my head gasket is not blown, then.. bam! you just have to go and say something like that..... Can't a man just live in blown-head-gasket-denial for just ONCE in his life??

Ok, no, nevermind, I'm not mad! I appreciate all your critical advice I promise! Yaaaay!

Yup

I'll look into it

 

Yesterday I drained the stuff out of the cooling system after driving around for two days with the Blue Devil additive in the water to help it clean everything out.

It was pretty dark, dirty and nasty. That should be about 30% old coolant (hor however much remains in the block after draining the radiator), 65% distilled water, and 5% blue devil flush additive.



This is what inside the head's coolant passage looks like with the thermostate removed. What the hell is in there??



I removed the old water pump and inspected the blades and they were perfectly fine. I'm 99% sure there was nothing wrong with the old water pump now, but I had to be sure.

Next, I smoothed out the inside of the thermostat housing to help flow. The inner angle of the right angle bend was particularly sharp before applying the dremel to it.



I did a little science experiment to see which thermostat I wanted to use. I had a 195*f one from Oreillys, another 195*f one from Autozone, and 180*f Stant Superstat from amazon.

I bought the 180 superstat thinking the extra 15* would give me a heads up that the coolant temp is creeping up again. I know that it wouldn't help the cooling system shed heat any better. But after reading that the engine needs to run at the temp it's designed to (the motor oil performs better at that temp, the computer and O2 sensor like it better too, and it gets better gas millage) I thought I would return it or put it on the shelf somewhere..



Turns out that the two cheap 195*f thermostats opened up well before the 180*f superstat! So that's what I chose to use. Maybe I'll buy a proper 195*f superstat later down the road...

Although the old water pump was fine, I put in the new one just because why not, it's not that expensive and I already had purchased it.



Now I just have to put everything back together

 

What did the inside of the water jackets behind the w/p look like? The crud inside the thermostat housing looks like mineral deposits I've seen in well pumps (such as limestone). I really hope what you've done solves your problem but if the water jackets inside the engine look like that housing I don't know.

 

The cylinder water jacket area wasn't nearly as dirty. It looked fine really, like black metal is how I would describe it

 

are you using the city water? getting most of it out before refill? making sure you burp all the air out of the system?

 

This is why I put the Gano filter on mine keep scale from entering radiator .

 

I would pull the temp sensor and clean the probe off...

 

The mix of what I estimate to be 30% old coolant (or however much remains in the block after draining the radiator), 65% distilled water, and 5% blue devil flush additive after letting the flush additive do it's job for two days of normal city driving:



Is it possible that it was just super dirty in there and the coolant just couldn't shed the heat of highway speed driving? This is the 2nd time I've flushed using an additive.

This is the new lower radiator hose:



The parts store had a LHD and a RHD hose (for LHD or RHD radiator?) and I simply brought in the old one to compare and get the same one. I got the LHD one. Actually they didn't have the RHD one in stock so I couldn't compare it to that one or see what that one even looks like

But after installing it, one of the bends is half-way kinked by default!



Do you think I could have the wrong radiator hose? I'm trying to remember if I got the RHD or LHD radiator... either way after getting the new radiator the old hoses fit it fine (or so I thought) but the oil cooler line fittings where on the opposite side than the old radiator.

It's a Left Hand Drive jeep and I guess the difference is where the gearbox is located, but I think what I might do is find a RHD radiator hose and see if it fits better...

oh and one more thing, neither my old hose or the new hose had a spring inside it. Do I need the spring you think? Is there a universal hose spring I could use maybe??

[UPDATE: Amazon reviews http://amzn.to/2s981b3 say the hose comes a little too long from the factory and that it needs an inch chopped off. This will probably be all thats needed to remove the half-way-kinked bend I hope!]

Here this should help:



No I'm using distilled water. When I drained the old coolant out, I drained the radiator and then filled it back up with distilled water and flush additive. Then I drove it for a few days, and then drained it. After removing the water pump, hoses and radiator I flushed it in reverse direction with the garden hose. Then I poured a gallon of distilled water through the thermostate opening in the head which should have replaced all the tap water in the block with distilled water. What I usually do to burp the air out is park it on a slight incline, start the motor with the rad cap removed, and add water as needed while also pumping/squeezing the top radiator hose.

 

The mineral deposit can be frustrating to get out! You can lightly pressure wash through the front of the engine with the water pump and thermostat housing and upper and lower hoses removed from the engine
but be very careful and remove the engine coolant drain plug from the block