v8 t-stat, what else should i check Options

[smrz914]

So i took my t-stat out and put 3 1/8" holes in it. Anything i can/should chech while i'm in there?

[Brad Roberts]

Use a good Fel-Pro gasket (blue one that can be reused over and over).

Most of the time.. we gut a stock T-stat. You just need some kind of restriction to slow the water down in the radiator. If it moves too fast.. it doesnt get cooled down properly. Each radiator setup out there may require more or less restriction depending on what you used for a radiator and lines. The Renegade badass setup seams to only need the small holes in the t-stat.


B

[smrz914]

The Renegade badass setup seams to only need the small holes in the t-stat.

But they still use a t-stat.

I've been having cooling issues (yea I know buy the renegede system, but being a college studenti can't), I will overheat anywhere, in town on the freeway etc. But if i'm on the freeway and she starts to get hot and i let the car coast then after a little coasting i can let the clutch bac out and continue driving and the temp will jump back down to 180-190 and then go up again. It and i keep doing this over and over. So this i can do this anytime as long as i'm moving, but when i was comming home from school on I-5 I was doing over 80 and was able to keep the temp at 210 along with giving a Audi TT a run for it's money. BTW I also have a stock transmission $k rpm about 80.

[boxstr]

Paul Have you tried the thermostat that John Thomas refered to from Summit racing?? Seems like that is what helped to cool him down, as well as the 3/8" holes.
CCLIN914-8

[John2kx]

Paul,

I saw your similar post over on porchev. It's clear here your fighting a cooling issue. What is your temperature at highway speed? How high does it get (max.)?

What happens at extended idle?

Are you using a expansion tank? Where is it mounted? Does the coolant in expansion tank always come back to same level after car is completely cooled off (over night)? If not, you've got some sort of leak (internal or external) that could lead to high operating temp.

RH recommends a 16lb. radiator cap.

Do you know how to burp system?

Who's water pump are you using? Since you didn't have bleed holes in your thermostat, there is a chance you damaged impeller if rpm exceeded 2-3000 before t/s opened.

Have you checked all hoses to ensure no kinks exist in system?

I saw pics of radiator on your website. Do you have any others of engine bay and or hose routing?

John

[smrz914]

Paul Have you tried the thermostat that John Thomas refered to from Summit racing?? Seems like that is what helped to cool him down, as well as the 3/8" holes.
CCLIN914-8

I do have that t-stat Mr gasket I belive. FYI On the pors-chev list it says 1/8" holes.

[boxstr]

Correct you are.
CCLIN914-8

[smrz914]

I saw your similar post over on porchev. It's clear here your fighting a cooling issue. What is your temperature at highway speed? How high does it get (max.)?

My gauge shows above 260 and this is taken from the side of the block b/c the relay that turns on my fans is connected the the intake.

What happens at extended idle?

Get's hot

Are you using a expansion tank? Where is it mounted? Does the coolant in expansion tank always come back to same level after car is completely cooled off (over night)? If not, you've got some sort of leak (internal or external) that could lead to high operating temp.

My expantion tank is mounted in the rear trunk. It seems to work properly and levels seem to be normal and consistant.

RH recommends a 16lb. radiator cap.

That's what I got.

Do you know how to burp system?

I hope so, no one ever gave me instructions and i think i have tried most posibilities. I even went as far as widdleing down a peice of hose so it fit's inside the t-stat opening and connected the other end to the bottom of a bucket. Then i ran the car and water worked it's way into the bucket and then a whole bunch of water entered the bucked and then vacated. So the water cycled up and down every 3 or 4 seconds. This is also something i find odd.

Who's water pump are you using? Since you didn't have bleed holes in your thermostat, there is a chance you damaged impeller if rpm exceeded 2-3000 before t/s opened.

Interesting because my first one from Renegade hit the fan (one of the impeller blades came off so I went to my FLAPS and they found me a replacement out of steel and not aluminum. The pump is a suspect being that the shaft that connects the pully and the impeller might be slipping.

Have you checked all hoses to ensure no kinks exist in system?

The hose is either the green stripe hose that renegade recomends or preformed sections to make curves. I can't find any kinks.

I saw pics of radiator on your website. Do you have any others of engine bay and or hose routing?

That's my old radiator and I haven't had a chance to take new ones, But it's a big aluminum radiaor w/ 2 12" fans that put out 1050 cfm each. Hose routing is underneath the car.

[rick 918-S]

When to temp gauge gets up to 260 does the cap release?

Are you loosing coolant?

Or is the gauge just showing high temps?

Iron block motors with iron heads really generate more heat than ally motors. Specially when you shut them off and they go into the heat soak mod.

Get one of those gun type pyrometers and check to see the gauge is accurate. When the high temps start showing you will be able to take a reading at the front radiator inlet side and the outlet side, then the return at the block. This will tell you if you have a flow problem.

I'm not sure if you know what the function of the holes in the t-stat are for. I was always told the holes would allow trapped air to purge past the t-stat. If the system is air bound it will cause the over heating problems to persist.

Expansion tanks should be mounted higher than the water jacket if possible not lower like in the rear trunk.

[Mueller]

blown head gasket???

Paul, I have a snap-on rad/coolant pressure tester if you need to borrow one, let me know and i can put it in the mail for you

[John2kx]

(QUOTE) My gauge shows above 260 and this is taken from the side of the block b/c the relay that turns on my fans is connected the the intake.

260 is too damn hot! Is this the way it has always run or a recent problem?

[QUOTE]What happens at extended idle?

[/QUOTE]Get's hot

So you have high operating temp. at idle as well as at highway speed? Just so we are clear on what you call hot........do you see 260F in both situations? If you start car and just let idle, will it reach same high temp. as while on highway?

[QUOTE]Are you using a expansion tank? Where is it mounted? Does the coolant in expansion tank always come back to same level after car is completely cooled off (over night)? If not, you've got some sort of leak (internal or external) that could lead to high operating temp.

(QUOTE) My expantion tank is mounted in the rear trunk. It seems to work properly and levels seem to be normal and consistant.

I would move expansion tank to engine bay and mount as high as possible. This will help eliminate air entering system during cool down. The long length of hose to rear trunk and its low mounting position is not the desired setup.


[QUOTE]Do you know how to burp system?

[/QUOTE] I hope so, no one ever gave me instructions and i think i have tried most posibilities. I even went as far as widdleing down a peice of hose so it fit's inside the t-stat opening and connected the other end to the bottom of a bucket. Then i ran the car and water worked it's way into the bucket and then a whole bunch of water entered the bucked and then vacated. So the water cycled up and down every 3 or 4 seconds. This is also something i find odd.

This is not the proper way to purge air from cooling system and may be the root cause of your high operating temps. This is the procedure:

1. Fill system from high point in engine bay. Leave radiator cap off overnight and let excess air excape. Top off system after allowing to sit overnight. Hopefully you have a radiator cap and fill point in engine bay mounted higher than intake manifold.

2. Start engine with radiator cap (in engine bay) removed. Watch water level at this location and how it flows now that you have bleed holes in t/s. You will see air bubbles work their way out of system at this point while engine is running. This will take about 5 minutes as engine gets up to temperature. Have radiator cap handy since water in system will expand as it warms up. Install cap with engine running as water level starts to escape at this point. DO NOT turn engine off at this point of procedure.

3. Take car out for a drive and get up to opeating temp. Turn car off. When fans are about to turn off (about 170F), open petcock at top of RADIATOR to remove air. You will see a mixture of water and air escape. When you get a solid stream of water, shut off petcock.

4. Do this a couple of times and you should be ready to hit the road.


[QUOTE]Who's water pump are you using? Since you didn't have bleed holes in your thermostat, there is a chance you damaged impeller if rpm exceeded 2-3000 before t/s opened.

(QUOTE) Interesting because my first one from Renegade hit the fan (one of the impeller blades came off so I went to my FLAPS and they found me a replacement out of steel and not aluminum. The pump is a suspect being that the shaft that connects the pully and the impeller might be slipping.

Hmmmmm.......the first damaged impeller was most likely caused by not having bleed holes in thermostat and running engine above 2-3000 rmp before t/s opened. Since you just drilled holes in your t/s, you may have performed the same damage again to new impeller. Unless you measured your old impeller with the new one, I would question if the clearances (impeller to water pump housing) are the same. If they are not, the water pump will not work as designed. Go after this last since it is the hardest of what I'm asking you to do.

[QUOTE]Have you checked all hoses to ensure no kinks exist in system?

[/QUOTE]The hose is either the green stripe hose that renegade recomends or preformed sections to make curves. I can't find any kinks.

The tightest turns in system are the hardest to see. Double check the hoses running from water pump to front of engine block. This is where you can run into trouble due to lack of visability in addition to tight fit at bulkhead. Run you hands along hoses going to front of block or check from underneath car to ensure no kinks are present. This one bit me once.

I'd still like to see recent pics of your installation as it would be more benefical than a brief description.

Other:

1. Have you altered the timing lately?

2. Changed air/fuel ratio? Both can effect cooling temperature.

3. Your method of measuring water temperature is not correct. Since water flows from water pump to block, then to heads and then intake, the desired probe location would be intake. Your 260F reading might be higher than what your seeing now.

4. What are you using to measure temperature? I've seen false readings caused by $10 gauges. Does your engine have that "I'm hot" smell after a highway run? If you are really running 260F, you should be able to smell it and even hear some weird sounds when engine is shutdown.

John

[John2kx]

Sorry for the mess guys........this was my first attempt at using the "quote" thingy. Looks like I f_cked that all up.

John

[rick 918-S]

You can go back and edit out what you don't want.

[boxstr]

John You got your point across. Good job.
CCLIN914-8

[smrz914]

When to temp gauge

Are you loosing coolant?

Or is the gauge just showing high temps?

Not loosing coolant that as far as I can tell. No white smoke out the tailpipe nor have there ever been coolant drippings under the car. And the level in the expantion tank returns to a constant level.

Get one of those gun type pyrometers and check to see the gauge is accurate. When the high temps start showing you will be able to take a reading at the front radiator inlet side and the outlet side, then the return at the block. This will tell you if you have a flow problem.

Guess it's time to buy one.

I'm not sure if you know what the function of the holes in the t-stat are for. I was always told the holes would allow trapped air to purge past the t-stat. If the system is air bound it will cause the over heating problems to persist.

I'll put the car back together tomorrow and see if the holes did anything for me.

Expansion tanks should be mounted higher than the water jacket if possible not lower like in the rear trunk.

The expantion tank is right up against the engine/trunk wall and wouldn't get much higher if it were in the engine compartment. I would say that the bottom of the tank is at about the same level as the bottom of the intake.

[smrz914]

Paul, I have a snap-on rad/coolant pressure tester if you need to borrow one, let me know and i can put it in the mail for you

That would be very helpfull. I'm only about 40 min. from antioch so would be willing to pick it up. e-mail me when a good time and day would be smrz914@hotmail.com

[John2kx]

Paul,

It appears you have not been using the right procedure to bleed air from system. Armed with your new thermostat and knowing how to bleed system, you may have found your problem.

The extended distance expansion tank is located from fill point can cause air to enter system. If you used a clear hose to run from fill point to expansion tank, you'd see the air pockets that can form in hose using your method.

See attached:

John

[John2kx]

adf

[John2kx]

I doubt your water pump impeller is slipping on shaft. My installed impeller as well as my spare are both made of steel. No aluminum used on impeller..........only water pump housing is aluminum.

John

[John2kx]

let's try that again