Overheating

[rnoswal]

Well, I got the thermostat and drove it around a bit last night. I almost thought it was cured but it started tooverheat again during the drive.

The fan has a shroud, but doesn't cover the whole radiator. I need that row of two fans that is supposed to come with the radiator originally. It is getting too warm where there is now air flow. I think I will try making a lower cover to close th underside off and force the air to go through as much of the radiator as possible.

I do not think it is the head gasket. I just rebuilt the engine and like I said before, I feel confidant in that area. Now I may try to bump up the torque number like I saw "Supra Girl" (supra girl music here).....lol. But it torqued down evenly.

Like I said before, I don't like the impeller setup on the water pump though and thinking that it may be causing some of the bubbling in that area. I did notice a difference between makes of water pumps though. Some had deep blades while a few others were shallow. I suppose I should break down and buy the proper TOYOTA pump, $95.00 ouch!

Keep up the suggestions as they are what is keeping me motivated to continue with this......................thing.

Thanks
Russ

[Poodles]

Those fans on the side are for the A/C system, and they never come on unless your A/C is on (at least on my car). I'm honestly starting to think it's the radiator now, since the stock units are copper and are prone to clogging (had the same problem in my toyota truck). Replace it and see what happens, couldn't hurt, though it's harder to get a really hot heater in the winter with a really good radiator.

I haven't used them yet, but someone posted the link to cheap supra parts, and they have a water pump for about $70

http://www.trademotion.com/partlocator/ind...m?siteid=213747

I'm doubting it's the water pump though, as putting the thermastat in it fixed a lot of it, which means it's moving the water plenty fast, and the thermastat slowed it down so the radiator could work.

[ddmcse]

for online reference . i have comments but can't post em right now

lemme say this for now

been there ,done that .

replacing this pump wasn't the answer for me either

you mention boring the blocks but what about surfacing the block(s)

what block got surfaced what block didn't?
are you using a metal gasket ?
could you have switched hoses going to and from somewhere ? kinda sounds like one hose is pushing when it should be pulling ..thats assuming it's not a bhg .
i have had my car for 10 years . i struggled with the same problem for about 60k miles . water pumps hoses radiators you name it , sensors swicthes anything i could think of finally she quit .
i swapped engines , and blew another gasket after 10k miles this was a remanu from japan . went with the metal blew that one in less time and had finally had it . i resurfaced the block by hand . had the head surfaced by machine and then did the head by hand . the two parts are beyond smooth . can you say badda bing ?

i've dealt with 4 bhg's on two different supras ....... they really suck .
flat and smooth

the picture makes the flaws easy to see but with the human eye the flaws are not easy to see and you can barely feel them .
i know it looks like grand canyon , but you can see the difference that the lapping tool made .
when i got the head back from the machine shop the guy there thought i was nuts for touching the head after he finished it . but the head looked like it had grand canyon all over it and i could feel it too . lapping the head made a big difference.. hand beats machine

one thing i've always thought about but never looked into is the pipe that runs along the entire block- exhaust side

it's coolant, it's a level pipe .. i just wonder what happens inside that pipe and whats stuck there or how plugged it could get .like i said i never looked at mine but it makes you go.... hmmmm

[rnoswal]

Well the waterpump pictures are appreciated. They all are the same I guess, just seems weird though. The mating surfaces on both the head and block were machined and very flat. I tried a few heads that had the water channels eaten out by electrolisis and that is where they never sealed well enough and leaked. This basically new head has no pitting nor any irregularities on the surface. It was checked before I bought it so I don't have first hand knowledge on actually seeing the checking being done.

The block was machined by a shop I regularly do business with, but no one is perfect! I don't seem to be losing water anywhere, it just doesn't seem to want to stay cool! I started with the fan and new fan clutch and a fan shroud. This shroud was from an older car and no electric fans for the A/C, but I don't have a compressor right now anyway. The fan clutch would run fast when it was cold but would slow down the hotter the engine would get. Sitting there idling it would eventually overheat.

With the electric fan, one big 16 incher, idling it will not over heat, but the side it does not cover does get hot. I thought driving it around would get air through that area so I tried it. Around town, not bad and it is hot down here in Louisiana, it managed to stay normal on the guage. As soon as I get on the freeway though the temp starts climbing. If I turn the heater on high, it doesn't go up as quick but still does go up. When I return to stop and go driving, it kind of stays where it is but slowly climbs, never drops.

The radiator is about a year old, aluminum, single core, 1" cores. I checked the parts house and the turbo takes the same radiator. There is no blockage of air from the A/C parts in front of the radiator other than normal. I am not sure about the smaller hoses running to various parts on the intake, but they will only fit at the places they go to. I replaced the heater core last year too, it was leaking.

It seems that the cooling portion on these cars is marginal at best. I know up north it might be better and maybe the car wasn't designed to cope with the heat down here, I know I am not!!!.....lol. I will keep working on it. I will find a smaller fan for the open side of the radiator and try to seal the bottom off between the airdam nose to the front crossmember.

Speaking of the water tubes running the length of the block. At the back corner on the exhaust side the is a port that is blocked off with a rubber cap. I don't see where it could go to. The heater hoses seem to go to the right places. Just wondering.

Thanks
Russ

[ddmcse]

i got the same cap off thing . blew it once a long time ago when i first got this car .

is it actually overheating still (water gushing the whole works) or is your temp gauge going crazy and/ or making you crazy ?

[ddmcse]

i think 20 minutes with the cap off is going to cause the water to blow out .
i don't trust my stock temp gauge and i sure can't trust yours .

what other over heating signs do you have ..

how about the extra water bottle up front is that pissing out onto the intercooler?
with the current setup has it actually over heated or maybe you have bhg paranoia (hey i've been there and i'm still getting treatment)

[rnoswal]

Well, Iput some water wetter in the system and am going to drive the car towork for the first time in a lot of months. I am not losing water when the engine isn't running too hot. When I do lose water, the guage has pegged or close to it and it blows it out the overflow bottle in front of the A/C condenser/evaporator, what ever that radiator looking thing is called. I can hear it boiling in the system and the bottle bounces all around while throwing up water. I am probably going to try a dual fan setup later on. I have one 16" fan and can't find one small enough to fit next to it, about 8" would be just right. So 2 twelve inch fans may be the way to go.

I guess with the engine over heating on me lately, many out there would think that I should have a bhg by now, but not yet. I haven't been pushing it and let it cool down naturally.

I think I need to work on flow through the radiator at speed. I have said it before though, I think the cooling system has been marginal at best. I think the radiator is too small and I think the pump lets the water stay too long in the block. That is a long block and maybe the water jackets weren't designed large enough, I just don't know. I raced a Toyota Celica 22R engine for quite a few years with rpms running up to 7800 prms and the engine always ran cool. Large radiator and good flowing system and no fan shroud! Go figure.

I hope I make it to work without getting pissed at the steam coming out of it again. I will let you know. The cap is pretty new and I will check the ignition timing tomorrow. I set it to where it just stopped detonating and then retarded it a bit more, just a bit. Who knows maybe that is my problem or part of it.

Later
Russ

[ddmcse]

i would only use toyota parts for the cap and thermostat .

i tired to stuff 2 elect fans onto mine too .. i took off the a/c fans and all the a/c i use (1) 14" perma cool elec fan and a 4 inch shroud made to fit around the fan , smack in the middle , i'm using a fluidyne radiator . i drove around yesterday for hours up and down all kinds of hills . it's seems great however i can never really relax...i always watch the gauge . i crap my pants once the temp gets to 190 degrees . the car seems to be a cold blooded beast . after the sun goes down and the temp cools off it will drop to 160 degrees . i get no bubbling or spitting but i refuse to run at water temps of 200 plus .. if it gets or starts to climb over 190 i start taking cool down action . use the heater--- coast all that patented supra cool down stuff . i'll pull over and chill for a second , i just can't handle driving above 190 .
you got some horse power behind the thinking on this problem hopefully we'll come up with the solution .

[ddmcse]

do you have a service manual ?

http://www.cygnusx1.net/supra/library/TSRM...M/co/CO_01.html


kinda funny the cooling system is the smallest section in the service manual