XimbueX

I've read through most of the other cooling threads, but haven't gained much insight yet. I haven't drained the coolant from the block yet, but here's the rest of the story.

I have a cooling problem that has me stumped on an 87 TII. Idling or driving it's the same... I have taked off the water pump to inspect it, and sealed it back up. I've put a known good radiator, thermostat, hoses, fan etc on the car with so signifigant differences. The car had the nipplies on the part the caps go on, one of them was going to the overflow tank, the other wasn't hooked up to anything. I put the piece the cap hooks onto from my 88 w/o the nipple on the water neck, but that didn't make a difference either.

The coolant starts to boil when the temperature gets to about halfway, I've bled all the bubbles out with no signifigant difference.

The overflow tank had a bunch of junk in it, most likely rust goo, I replaced that with a clean one.

Anyone have any ideas? I think the engine is okay, as no bubbles come up when I crank the engine over.

Thanks,

.[ matt ford. IM:XimbueX
.[ 88 GXL. -> Modded [to death (literally)]
.[ 87 TurboII -> Fresh Canvas
.[ Mazda Sports Car Club of NC http://www.msccnc.org

J-Rat

iTrader: (2)

Check the fan clutch..I was overheating like a *****, and it looked like the fan clutch was good. Well, I decided to keep spinning it by hand for a while...After 10-20 turns, it started freewheeling. So I tossed it and got a 12-blade electric fan. Now its running cool..

XimbueX

I put the fan from my 88, which always ran very cool into the other car w/ the problems and there wasn't much improvement. Maybe a little, but not a whole lot.

J-Rat

iTrader: (2)

I dunno....I flushed the **** outta my system. Then put the electric fan in and it started cooling down. Oh, and I replaced the thermostat too. But before that, it was doing the same thing...Boiling at the half way point.

J-rat

XimbueX

What method did you use to flush the system?

thanks
matt

J-Rat

iTrader: (2)

I took all the hoses off and the fan shroud, and hooked a hose up to the top of the radiator. THen I just flushed it at full blast till the water came clean. Then I went, had a beer and a smoke, came back and did it all over again. Then I removed the thermostat, and flushed out the block the same way. Took a good long while, but there was some SERIOUS sludge in my system (brown rusty looking junk). Then I refilled it and went for a drive!

XimbueX

when you flushed the block, did you have to do anything to get the water to flow through correctly besides just putting water straight through the thermostat opening?

I tried the prestone flush kit today without any good results, but I think it is because the kit says to Tee into the heater hose, but for some reason I don't think that gets water through the block correctly.

thanks,
matt

J-Rat

iTrader: (2)

YOu can pressure flush the block if you want...I didnt...I just hooked up a tube to the hole where the Thermostat was and shot water into it. Its been my experience (maybe 7s are different, I dunno) but most of the sludge and gunk ends up in the radiator and the overflow. The block remains relatively clean due to the size of the water passages. I didnt get real tricky with flush kits and the like..I dont really believe in them. I will, on occasion, use radiator flush though...Gets more of the junk out.

Rat

Matt22

iTrader: (10)

**** maybe i should totally fulsh my system.
Matt22

XimbueX

There was a ton of junk in my collant overflow, a bunch of nasty ****. But like you said, I think my block was pretty clean too. I still have cooling problems though.

The only thing I haven't replaced is my water pump, but I did take it apart and check it out, it it seemed to be in pretty good condition.

I really wish I knew what was causing the overheating.

Matt
87 TII

J-Rat

iTrader: (2)

Hmm...I dunno. Are you getting heat from the heater? Usually all that tells you is that you have no water, but you know you do..The overheating problem is the easiest to fix. It can only realistically be a few things. One thing I did do, was take the hose and run water from the engine bay OUT towards the front of the car to get all the dirt, bugs, neigbors kids, etc.. outta my radiator. Your radiator may also just be too old and clogged to cool anymore. When you removed your water pump, did you spin it? If you did, did it have resistance? Did you wiggle the pump shaft? If you did, did it have any play? No resistance and play in the pump shaft are sure signs that your pump is ready to give it up. Lets see...New thermostat, new fan, and your car isnt spitting coolant when you start it cold, full of fluid...Hmmm... Gotta be either the seals, the radiator or the pump..I cant come up with more then that.

Rat

XimbueX

The water pump seemed to be in good shape, but there was some rustiness to it. I am going to flush it again using another method I read about, then if that doesn't work I am going to put the pump portion from my n/a into the housing on the T2.

I know for sure that the radiator works because it came off of my n/a which always ran less than 1/4 on the temp guage no matter how hard I was driving. I also swapped the thermostat, cooling fan, and the hoses which were damn near new. As well as the coolant overflow hose and bottle.

After flushing last night, I put on new rad caps and went for a drive. I was still hitting 3/4 on the temp guage but the coolant wasn't boiling when I got home like it had been doing before so hopefully I'm getting closer to the source of the problem.

thanks again for all the help.

-matt