Cant get right part!

suprahabsfan

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Sep 28, 2007
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What aftermarket radiator cap fits! I've bought a TRD and a blitz and had to send back because they were too small! Any help? I'm losing my ass on shipping charges! Have to pay to get it here and send it back!
 

87mgte

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Sep 9, 2007
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Why would you get an aftermarket radiator cap? That's like wasting money on an HKS dipstick and windshield wipers just to say you have more HKS parts in your car. Go with an OEM cap.
 

HommerSimpson

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Dec 31, 2007
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suprahabsfan;1012033 said:
Like I said before, it raises boiling point, and improves cooling. Does anybody wanna help or just make fun of me for wanting one?

You do not want to over pressureize your system.... Use a factory cap... Rasing the boiling point like 4deg by every lb is not what you need on your toyota.....
It does not help cooling.. it only allowes system boiling point to raise..
 

Supracentral

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Mar 30, 2005
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Aluminum anneals at the same temperature, regardless of how high your coolant boiling point is. If your car is getting hot enough to boil your coolant, you've got far bigger problems.

With that said, do you have a factory radiator (plasitic top) or an aftermarket? This matters for cap fitment.

Btw, factory rad's tend to develop spits in the plastic endcaps when over pressurized.
 

suprahabsfan

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Supracentral;1012047 said:
Aluminum anneals at the same temperature, regardless of how high your coolant boiling point is. If your car is getting hot enough to boil your coolant, you've got far bigger problems.

With that said, do you have a factory radiator (plasitic top) or an aftermarket? This matters for cap fitment.

Btw, factory rad's tend to develop spits in the plastic endcaps when over pressurized.

I have a OEM Koyo replacement, all metal.
 

Supracentral

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suprastanger507mgte;1012066 said:
The Ones designed to fit a 7mgte radiator cap should fit it then.

Correct.

suprahabsfan, are you sure you aren't being given MKIV rad caps?

For the Blitz 1.3 bar cap, the stock MKIII rad uses the blue cap (#18560), not the red one (#18561), which is used on the MKIV.

If blue cap doesn't fit, your radiator does not use the OEM cap size and they gave you a weird one.
 

suprahabsfan

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Sep 28, 2007
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I ordered them right, I know that, but they are too small. Which color blitz is equal to the TRD cap? I'll order the opposite because the TRD did not fit.

By the way, all tests (block test kit, compression test) came back fine. I am using a HKS MHG torqued to 80. No overheating, no gurgling, no temp gauge spikes etc. I UV dyed system and couldn't find any leaks. I KNOW it has to be a pinhole leak somewhere where I'm losing pressure, and the water is boiling, I just can't find it. So, with a well made, 15psi cap, I can rule out the cap, and not have to worry about my cap again. Plus it may blow the radiator hose and then I'll find the leak and just replace the hose and it will be done!!!
 

Supracentral

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The TRD cap with a part number of 00642-16401-003 probably the one you need, but I wouldn't swear to it.
 

jdub

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The stock cap is holds between 10.7 and 14.9 psi...you are not improving anything by using a higher pressure cap. In fact, you risk blowing hoses or worse case, a block freeze plug. I'm not making fun of you, but what you're doing does not make any sense.

Are you running a 50/50 mix of coolant to water? Is your fan clutch in good shape?
 

suprahabsfan

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jdub;1012100 said:
The stock cap is holds between 10.7 and 14.9 psi...you are not improving anything by using a higher pressure cap. In fact, you risk blowing hoses or worse case, a block freeze plug. I'm not making fun of you, but what you're doing does not make any sense.

Are you running a 50/50 mix of coolant to water? Is your fan clutch in good shape?

Yes and yes. I suppose I should buy a OEM one from toyota. I'm worried about getting the wrong one even still.
 

jdub

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Yes, you should get a stock cap. ;)
Stant makes quality caps as well.

One thing I always do is cut the jiggle valve off the thermostat. Provides a small flow at all times and helps keep the system free of air. Hard to say if will help in this situation.

Since you UV dyed the coolant, did you check under the drivers side dash for heater core leaks?

Also, did you do a cooling system pressure test?
 

suprahabsfan

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I only compression tested and Block tested.

What is that jiggle valve? No I didn't check under dash...in the car under the dash? Im just so sick of stopping in a parking lot and people telling me my car is leaking. My car runs so smooth and well, but this makes it look like a piece of junk. Im so sick of putting in coolant.

I have a stant in there now, my dealer has a OEM cap in stock, gonna try that I guess.
 

jdub

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Jiggle valve is labeled in the bottom pic:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=CO&P=8

Yes...the heater core is inside the car.

If people are telling you it's leaking, where is it dripping from...i.e. where does the puddle from under the car?

There's several areas on the motor where it would be very hard to see coolant leaking. The hard line around the block connects to the union at the back of the head (there may be a plug on a unused fitting here too), the heater hose at the same place, a 90 deg hose behind the water pump, the TB/ISCV lines and heater return on the drivers side. The TB/ISCV coolant lines are difficult to see.

Look at this diagram for more places:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?Section=CO&P=2

A system pressure test should make any leak obvious ;)
As you are probably aware, a new cap will not stop a leak...unless it's the cap itself.
 

gofastgeorge

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I run a SARD 1.3 BAR (19 psi) cap on my Toyo.
No problems what so ever,
and I don't even run the US style screw clamps,
just the OEM spring clamps.

You have to be very careful when ordering any JDM cap,
because the JDM Mk3s used the later style cap.
Distributors who don't know crap, just look in their book,
and it shows to use 'X' cap on a Supra,
but they fail to realize that the US market cars take the other, early style.
Most of the JDM companies offer both.
You need the Blitz 'Style 1' or a SARD 'S',
or one listed for either the early Toyota, or the Nissan fitment.

I have some of the wrong SARDs (type 'N') for the laterToyotas,
that I got out of Japan.
Return shipping was more than what the caps were worth,
so now they just sit here.
 

jdub

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Good for you George...just because you get away with it, makes it ok huh?
http://www.fallacyfiles.org/cumhocfa.html

The system was not designed for that high a pressure...there are many different places hoses can (and have) failed. Race car? Different story...just because you might want to use such a cap on a race car (with upgraded hoses) does not mean it's good for a DD.

BTW - the OEM clamps are a constant force type, superior to the screw type clamp. Toyota probably used them for a reason ;)