fixmiester

I found the lack of pressure rise corresponding with throttle jabs a little surprising at the time, but, at that point, there was no confirmation that the possibility of a system blockage had been eliminated, which could also invalidate this test.

djamps

I wouldn't expect pressure rising when a throttle jab. The pump really isn't that powerful -- Pressure actually rises because of heat. But if there's a huge air pocket, you won't see the pressure rise since the coolant just expands into the air pocket. And if some air is behind the Tstat (and assuming there is no air/bleed bypass around it like my cummins), it'll never open and allow any flow. Since you already replaced the pump, I'd seriously remove that Tstat and let the coolant flow freely during your troubleshooting.

Mtdave2

great point, it would explain why it is not pressurizing fully right now, and why it will, then wont. also it passes the leakage test! good input, thanks

fixmiester

That's what causes an increase in the flow; higher pressure inside the WP when reved and can easily be felt with your hand on the upper hose. But I missed the statement that he had replaced the WP; that may be an issue. Some of the replacement pumps come with a new gasket. Lexus uses FIPG ( not sure about a '95), not a separate gasket. Some folks decide to use the gasket, not realizing that it is designed for many different cars, and that if one is not careful it can be installed incorrectly, blocking the flow of the pump into the engine block. So, did these problems begin before or after replacing the WP?

Mtdave2

problems were from day one, even before replacing the wp, I have felt the pressure before in the hose, it just comes and goes. I am guessing the pump is caveating from bubbles caused by boiling of as trapped air pocket. ???.

dicer

I am not a fan of cross flow radiators, especially a single pass type, I remember in highschool days a friends dad mounted a down flow radiator on its side, to make it a cross flow, it way over heated never worked.

Mtdave2

well, that was really cool. I used the vacuum tool, if you don't have one get it! very cool, works like a charm. here is what i did.

Drained my coolant.
heater on heat
cap on, left the block drains open by accident.
removed one end of upper hose and attached the garden hose to it.
turnned on the water.

this forced water through the radiator, upper hose, through the motor and out the outlet to radiator.
now that I think about it, The bypass hole is open, so some of the water would have flowed through it, and out. Dam, Ill have to do it again and plug the bypass or go by a cheap thermostat, and remove everything but the plug. At the very least, there is no restriction in the radiator!

here is the video.

djamps

I just vac filled my cummins this morning and I'm pretty sure It sucked in more than I drained out... which is a good thing as I've been chasing a never ending air pocket lol.

Mtdave2

once I did that, I drained everything. closed up the drains, attached the hose. and used the cool *** vacuum tool. look what it did to the top hoses.

It did only get to 21 inches, the instructions say 22-24. but I think perhaps being in devner may effect it? very close anyway. I did a leak down test and it held steady for 5 mins. then I filled with coolant. coolest part of the whole thing. it empty a bottle in 20 seconds. very cool. and i didn't spill it all over like i usually do.

I did have to put normal hoses on to the expansion tank, my clear ones collapsed right away. after i did put a small piece of clear hose, so I can see the bubbles.







I then held the rpm at 2000. had a couple of small bubbles, then nota. no bubbles at all. temp climbed very slowly. It got to 204 and I let it idle. temp dropped to 177, never seen it that low. The upper hose pressurized, not rock hard, but firm. wasn't doing that before. I revved it while squeezing the hose, it did not expands as much as I think it should.

I took it for the normal test drive up the pass next to our hose.. no difference, I hit 240 as I reached the exit. as it always does. a major bummer.

so, what is the possibility of the pump blades being damaged from all the cavitation? I wish I had a pump to look at, to me it acts like if the blade unit was attached to the center rod with a pin, the pin fell out. still spins but slips on the rod.. know what i mean?

next steps? perhaps a drain and install cheap altered thermostat to plug by pass and do the garden hose test again. refill and try again?

What say you all?

Mtdave2

mine too, took in a good 1/3 of a bottle more im guessing.

Mtdave2

It is a dual core radiator. I am not saying you are wrong. perhaps it is a radiator problem. I just know others have the same set up and it works. Major issue if finding one that fits in the hole. I dont want a custom radiator because if you in an BF Egypt and need a radiator, Id like to say its a 85 jeep wrangler. not have to have a custom built and shipped.

Banshee365

It hit 240 after idling down to the exit or while under power? If you can duplicate it exactly, every time, try once or twice with running the heat full hot with the blower on full just before it would normally start to heat up and see if that makes a difference.

Mtdave2

going up the hill it is almost floored in 3rd, 3200 rpm or so all the way up. the temp slowly rises until i exit the highway (still up hill) usually hits 240 when im exiting. sometimes a few hundred yards before. I have done this with the heater on before, doesn't seem to make a difference. you thinking that as a test for a poor radiator performance?

fixmiester

You're making progress, now that you have eliminated the air pockets, but unless you perform the WP flow test I outlined, you will never know for sure if it is at least delivering normal flow, proportional to engine rpm. I can't provide specifics; this is a visual assessment performed at idle, then with throttle jabs, which should increase the flow by a factor of 2 or 3. If that passes, it may simply be a system design that is marginal, and can't handle the heat from full engine output. The air density up there will always be lower, and heat transfer will always be compromised. I know that's not what you want to hear, but it may be.

djamps

I'm following this thread closely and as things progress (assuming the WP and Tstat are in correct working order) I am also thinking there may simply be a lack of cooling efficiency. Let's assume the new vehicle weighs more and is far less aerodynamic (thus, engine working way harder than it did in the LS), the new radiator isn't as efficient, there is less air flow thru the engine bay, and an electric fan will never hold a candle to the large OEM belt driven fan...