Overheating RB26 saga, more info, help!

[underground]

Well, if anybody has an extra clutch fan setup that I could try, let me know..

I'm happy to pay shipping...

But, let's get some specs in terms of distance from the motor, etc. To see if it will fit....

I cut my core support and moved my radiator nearly two inches forward, so maybe it would work...

I'm still not sure this is the problem though..

[R31Nismoid]

That has to be it ay?I've heard nothing but bad from electric fans in place of the clutch ones!!

one of the guys here in Vic uses one.

one big one on the 33-t, no overheat problems on a hot day

[RBsileighty]

I'm not running a 26... but with a 20 and a FMIC that you can see in my sig... my 2 permacools do just fine. Since I fixed my leak on the back of the turbo I've had no overheating problems or temp change off "normal" in 40C deg weather with 80+ % humidity.

Did you bleed the air after you found the leak? I agree with Joel in that you should definitely make sure all of the air is bled from the system... that would be the cheapest fix if that's the problem.

As for the thermo... I'm running the Z32 TT thermo in my 20... but I can't tell you if you can use that in a 26... maybe someone knows if you can X-ref between a 26 and a 20 thermostat.

Here's some good info on cooling systems... http://www.mkiv.com/faq/faqtt.html#enginecooling

Good luck bud... sounds like your making progress... even if it is slow... it's still progress

[blind_elk]

Are you sure the thermo fans are working - do you have a pilot / tell-tale light for when they come on? At 100 C, they should be on permanently.

Try a cooler plug, say PFR6A-11, gapped to 0.8mm (approx 32 thou)

If the engine is running rich, then it's less likely to overheat, because the excess fuel helps cool the engine.

[underground]

The thermo fans are always on.. I have them wired into the ignition, so that they come on when the car is started...

The engine is running extremely rich...It reaks of fuel...

[blind_elk]

If you run retarded ignition timing, I think that causes the engine to run hot. Or if the cam timing is retarded, that can cause the engine to run hot.

Did you have the injectors cleaned before the engine was fitted into the car? Who knows what they picked up lying aroiund a yard for any period of time.

[underground]

I haven't checked timing yet, but that is something I plan to do next...

I was hoping to get the car to the radiator specialist today to have the coolant system pressure tested for leaks, but i got caught up at the tire place...

I was running 275/35/18 BFG Drag Radials, but they didn't handle outside of straight line. (But they were free, sponsored by BFG, so I can't complain.

So, I finally got some BFG KD's in today, 285/30/18, little less tire height which really makes a difference. So far, the car hasn't rubbed abit....

I will update this post tomorrow when I hear back from the radiator specialist...

[underground]

I had the cooling system pressure checked, but the results came back that everything was OK...

So, I don't think its a leak...

One thing I need to mention is that there is oil in my coolant overflow tank again...

I'm really thinking its a headgasket with a crack in it...

If it is indeed a bad headgasket, can I simply buy a new one?

Do I need to have the head machined? Or is this a simple plug and play deal?

[DAN00H]

If you have carried out an engine swap, you have no-doubt upgraded to a large front mount cooler as well. I think you are having air direction flow issues, in that the air is not going through your cooler or rad properly. Are you able to measure intake temps after the cooler?

you might find that the air is bypassing the intake duct and going under the car?!?!

As for the oil in the overflow tank - not good. Take the oil cap off and see if you have a creamy light coffee colour foam up the top of the cap (best to do it after a bit of a drive). if the gasket needs replacing, you will need to have the head machined for sure before fitting the new gasket.

See if you can put some padding between the outside face of the cooler and the edge of the front bar opening (most coolers do not sit flush with the bar opening, this can cause the air to take the easiest route AROUND the cooler and rad.

[Cubes]

Are you sure its oil?

Did you get a CO2 test done?

Oil will go a white sludge. not browny.

Mine went browny from lack of maintance, it looked like oil but wasn't.

[BensDR30]

Get a leak-down test done too, that will identify failing cylinders. 140 psi is pretty low for an RB-turbo.

*EDIT* Just had a look at the RB26DETT engine specs, compression should be 12.0 bar @ 300rpm = 174psi. Lower limit value is 9.0bar @ 300rpm = 130psi. Your engine is sailing close to the lower limit there....

99C is far too hot, something around 88-93 range is more like it. 97C when on a dyno at full noise with poor airflow....

[underground]

Are you sure its oil?

I would sure think so...

It looks like normal black slimy oil...

And NO, I havent had a C02 test done yet? I've never heard of this... Surely, after all these tests I've run, it would be obvious its a headgasket if it was..

I'm thinking that probably their is a small crack in the headgasket that is letting the oil in the coolant...

Unless its coming in somewhere else?

Guys, I'm so confused right now and hate to replace a headgasket if I don't need to..

It's 11:20 PM at night here, but I'm going to go up to the carwash and take a picture of the oilish substance in my overflow tank...

Chris

[underground]

Here's the pics...

The first one is the normal coolant color, I prefer Toyota Coolant as opposed to anything else stateside...

I drained the coolant and just took pictures of the residue that didn't come out with the coolant...

It's a slimy substance that obviously doesn't wanna flow out with the water, which makes me feel its oil of some kind... Has a black-brownish color to it.

[underground]

Those pics were taken with me putting my digital camera lense into the overflow tank... Hopefully you guys can make out what your looking for...

Also, just to add a little info, that car has been sitting for about 4 hours in cool temperatures as I live in the mountains and it's pretty chilly tonight...

[BensDR30]

A CO (not CO2) test is a check of the coolant for carbon monoxide. If there is CO in the coolant then combustion gases are leaking past the head gasket.

A coolant pressure test does not guarantee a result one way or the other. Only a leak-down test puts a 'reasonable' amount of pressure in the cylinder & allows you so sustain that pressure for long enough to determine the condition of the engine.

[underground]

I tried researching this CO test.... Where do you get this done at? I can't find anything online about CO testing for coolant...

I'm heading to a big city today here in the states where I could get it done most likely, but give me some guidance here...

[Beer Baron]

it's hard to tell from the pics, but in the fourth pic from the bottom there seems to be some sort of silt in that fluid? It doesn't quite look like oil to me. It's just a stab but an engine and full cooling system flush may sort this problem.

Richard

[underground]

it's hard to tell from the pics, but in the fourth pic from the bottom there seems to be some sort of silt in that fluid? It doesn't quite look like oil to me. It's just a stab but an engine and full cooling system flush may sort this problem.

Richard

I have had it backflushed, using a water hose and Prestone Do-It-Yourself Flush Kit at my house...

But, I really don't think its a blockage issue.....

I really feel there is another reason its overheating...

[underground]

Any other suggestions?

Come on guys, I need all the help I can get...

I really don't think its an airflow issue. I am going to have some custom induction vents built tomorrow to scoop air from the underside of the car...

I really feel this is something more mechanical...

[blind_elk]

Any decent mechanic should know about the CO test on the cooling system.

I would build an undertray that spans the front bar to the engine X-member. I had one on my Z years ago, and it was quite efficient at helping the radiator cool the engine. I was going to do the same for my R32 after I put a thermo on it. I could get the thermo to turn on even at highway cruise conditions in low 20s (deg C). But I put the factory fan back on instead.

Have I mentioned a series of articles at www.autospeed.com on siting undertrays and bonnet vents. I think you really need to be creating a low pressure region behind the radiator, so that air has to pass thru the radiator and cool the engine.