Yet Another Overheating Thread

[ShadowDrake]

Hey SVTP.

Help me out (please, I'm begging!)

I've done pretty much everything imaginable and can't understand what is happening.

04 GT - 4v swap using 01 continental heads.

I have made my own head cooling mod, bridging both of the rear freezeout plugs up to the heater core. Other line on the heater core goes to the back of the water pump.

I have bought and installed a reische thermostat. coolant temps when cruising are anywhere from 89-91 *c - better than the OEM 03 cobra t-stat I had in before.

I'm not using 100% of the OEM hoses in the cooling system, a couple are silicone. One of them - the one between the thermostat housing and block was collapsing when the revs came up - I reinforced it with a coil of wire and it's rock solid now.

The rest of the hoses seem to be fine.

The car will get into an "overheat mode" where the coolant temp will slowly rise, and keep going up. The radiator fan will come on first at low, then on high. The coolant temp will just keep going up. The upper radiator hose will be solid from the pressure. Eventually, the temp gets up to 118+ and the coolant boils and pukes out of the overflow reserve. There is a fix for this - if I shut the engine off for about 20 seconds, then restart it, coolant temps PLUMMET back to normal. I mean, 20-30 seconds to go from 115 to 90 (or lower) at idle.

Eventually it does it again. It seems to get stuck in this mode more often if I start the car after it is already warmed up. I don't drive it very far any more because it does this. Usually my drives are just a couple of miles and the car doesn't even warm up.

I'm at my wit's end though. My next fix is going to be to plug off the bypass circuit and just remove the thermostat and leave it that way.

When I refill the car (i've had to do it 6-8 times now because of this issue - when it goes to overheat it does it so quickly that the temp gauge doesn't move, it just boils over), I follow the reische instructions and make sure the cooling system is completely burped. I've used everything from straight water, to 60% water, 40% coolant, to water wetter. It's been tried, and faithfully refilled the correct way each time.

The thermostat is installed in what should be the correct direction (with the bottom going through the bypass loop). This reische thermostat is the 4th one I have tried. The previous ones are the OEM 03 cobra stant thermostat - NOT the incorrect 2v stat.

Anyone had this happen?

Suggestions?

Ideas? I'll even take wild shots in the dark. This is making me hate the car.

 

[006]

More details needed.

Where are you filling the coolant from?

Also post pics of your setup. We'd like to see this frankenstein creation.

 

[STAMPEDE3]

You meant 218°+ ?

If it is under pressuer it should not boil over at 218°

As Ken said, need more details.

 

[trxcobra]

You meant 218°+ ?

If it is under pressuer it should not boil over at 218°

As Ken said, need more details.

He mentioned he was measuring coolant temps in Celsius.

Assuming you properly burped the coolant system, I am not sure what could be causing that problem OP, I'm sure someone on here will help! good luck!

 

[shurur]

Heater core return goes back to the pump I think.

Those back freeze plugs (or at least the 7/8 driver's side head) should be brought to a T put in to the front of the upper radiator hose to get (some of) that that hot back head coolant to the radiator when in open loop.

I think as It is now..you're feeding the closed loop (engine heating) system-cycle-configuration constantly (in a sense) by not allowing coolant to flow forward through the heads to the bypass where it will go closed loop or open loop back into the radiator for cooling...depending on the thermostat.

Moving some of the Hot coolant through the heater core and back to the pump and though the engine again isn't going to help you much...and maybe hurt because it could have gone thruogh the heads forward to the bypass and on to the radiator for cooling.

If you're going to steal/theive/create-a-feedback-loop to the input with a little hot coolant from the back of the head ..I think you need to get it to a Tee in the upper hose to the radiator bypass tube (direction depending on the thermostat position).....a little hot coolant needs to bypass the heads, but go in the the same direction it goes in the heads....back to the radiator for cooling.

 

[ShadowDrake]

More details needed.

Where are you filling the coolant from?

Also post pics of your setup. We'd like to see this frankenstein creation.

Filling from the coolant crossover. I screw a funnel in there. Fill the overflow bottle first, close the top on it. Fill from coolant crossover. Start engine with funnel in place and coolant in funnel. Keep adding coolant to funnel, not letting air in. Rev a couple of times to get air out. Let it idle with coolant in funnel till up to operating temperature. Shut car off, keep coolant in funnel till cool. Siphon coolant from funnel and put plug back into place.

It doesn't look much different than any other 4v. I used my 04 GT block - iron. No modifications were necessary for timing equipment.

You meant 218°+ ?

If it is under pressuer it should not boil over at 218°

As Ken said, need more details.

I mean 118 * C - so that would be 245 *F. Definitely over boiling point.

Heater core return goes back to the pump I think.

Those back freeze plugs (or at least the 7/8 driver's side head) should be brought to a T put in to the front of the upper radiator hose to get (some of) that that hot back head coolant to the radiator when in open loop.

I think as It is now..you're feeding the closed loop (engine heating) system-cycle-configuration constantly (in a sense) by not allowing coolant to flow forward through the heads to the bypass where it will go closed loop or open loop back into the radiator for cooling...depending on the thermostat.

Moving some of the Hot coolant through the heater core and back to the pump and though the engine again isn't going to help you much...and maybe hurt because it could have gone thruogh the heads forward to the bypass and on to the radiator for cooling.

If you're going to steal/theive/create-a-feedback-loop to the input with a little hot coolant from the back of the head ..I think you need to get it to a Tee in the upper hose to the radiator bypass tube (direction depending on the thermostat position).....a little hot coolant needs to bypass the heads, but go in the the same direction it goes in the heads....back to the radiator for cooling.

The 01 continental heads have both freezeout plugs in place in the back. The coolant for the heater core in that application comes off of the crossover.

So I knocked out the ones on the top of the head for now. When the engine comes out for a rebuild with forged parts, I will switch them to the back of the head locations.

If I run the two freezeout plugs up to the upper radiator hose, I will need something to feed the heater core still. In OEM trim - the passenger side head feeds the heater core. The return goes to the rear of the water pump. This is essentially how I have it - only BOTH heads are feeding the heater core. That's the only difference in my setup currently. There's a head cooling mod (not sure which one by name) that does the same thing. LDC maybe?

I will draw up a crude diagram at work today - will post back at 6pm est or so.

This pretty much emulates the OEM cooling system from what I can determine.

When it works, it works just fine. I can abuse the car and it'll stay cool. If I start the car up while warm though it's like someone flicks a switch that disables the radiator.

 

[ShadowDrake]

Forgot to add, thanks for the assistance so far.

Here's a couple pictures of the engine as it was going together:

Note: In that last picture, that is the continental coolant crossover. I used that until I got a normal 01 cobra crossover. Notice the small line off to the left - in the continental that goes to the heater core - so that's what I did for my application.

 

[shurur]

The 01 continental heads have both freezeout plugs in place in the back. The coolant for the heater core in that application comes off of the crossover.

So I knocked out the ones on the top of the head for now. When the engine comes out for a rebuild with forged parts, I will switch them to the back of the head locations.

If I run the two freezeout plugs up to the upper radiator hose, I will need something to feed the heater core still. In OEM trim - the passenger side head feeds the heater core. The return goes to the rear of the water pump. This is essentially how I have it - only BOTH heads are feeding the heater core. That's the only difference in my setup currently. There's a head cooling mod (not sure which one by name) that does the same thing. LDC maybe?

I will draw up a crude diagram at work today - will post back at 6pm est or so.

This pretty much emulates the OEM cooling system from what I can determine.

When it works, it works just fine. I can abuse the car and it'll stay cool. If I start the car up while warm though it's like someone flicks a switch that disables the radiator.

*************************
YUP..I think you'll find that the LDC uses a TEE that also runs coolant to the front radiator hose as well as the heater core..and since the heater core input uses a restrictor, most of the hot coolant gets sent to the radiator and bypasses the heads a bit....we're getting there.

 

[006]

shurur has a point on how you're doing this wrong.

Also, your closed funnel method is wrong. You need to allow the crossover tube to vent out the air that is in your motor. from the instant temp change you mentioned earlier is very consistent with air trapped in the system and a wrongly setup cooling system.

The crossover tube should only be capped while he motor is already hot, the fluid is full and the air bubbles have stopped coming to the surface.

 

[shurur]

shurur has a point on how you're doing this wrong.

Also, your closed funnel method is wrong. You need to allow the crossover tube to vent out the air that is in your motor. from the instant temp change you mentioned earlier is very consistent with air trapped in the system and a wrongly setup cooling system.

The crossover tube should only be capped while he motor is already hot, the fluid is full and the air bubbles have stopped coming to the surface.

I had some book marks (HD crashed recently) from some chevy forums with some really nice bleeder systems with sight-glass viewers and the works...problem was $$$.

If a 1.5 " Tee on the front radiator hose was put in..could one drill a bleeder hole half way on one tee leg and bleed the system by pulling off the hose a bit until coolant bubbles out??...

The audi has a small weep-hole set up like that for the heater core bleed.

 

[ShadowDrake]

*************************
YUP..I think you'll find that the LDC uses a TEE that also runs coolant to the front radiator hose as well as the heater core..and since the heater core input uses a restrictor, most of the hot coolant gets sent to the radiator and bypasses the heads a bit....we're getting there.

Actually really good point about the restrictor.

I forgot that my stock 2v restrictor caused the line to explode one day while the car was supercharged and still had the 2v in it. I replaced the line and didn't use the restrictor again. I didn't have any problems like that and the car saw lots of flogging.

So it's unrestricted flow right now - and probably larger diameter hose than the OEM one as well. I probably have a minor issue here! On the flip side - the heat really does work awesome

What about the merits of the OEM setup though?

The OEM just has the passenger side head connected to the heater core (with a restrictor, I imagine), and the return connected to the back of the water pump.

The reason I did the head cooling mod is that I was still having the same overheating problems before. I didn't realize what was going on initially and now I have the head tick in the passenger side head :cuss:... But it's just one more thing to be fixed when I do the forged build.

I could probably rig up a bleeder system of some sort to thread into the crossover plug hole.

That is if I do genuinely have air trapped in the system still. It hasn't boiled over since I have last filled it and it's been a couple of weeks. I'll see if I can't get some more air out of it.

Got out of work late because I was swamped so the diagram will have to wait.

 

[ShadowDrake]

shurur has a point on how you're doing this wrong.

Also, your closed funnel method is wrong. You need to allow the crossover tube to vent out the air that is in your motor. from the instant temp change you mentioned earlier is very consistent with air trapped in the system and a wrongly setup cooling system.

The crossover tube should only be capped while he motor is already hot, the fluid is full and the air bubbles have stopped coming to the surface.

I just re-read and you're right. I'll go add more now and we'll see what happens. Done it so many times the instructions have blurred

Thanks! I'll be back with another progress report tomorrow.

 

[shurur]

I just re-read and you're right. I'll go add more now and we'll see what happens. Done it so many times the instructions have blurred

Thanks! I'll be back with another progress report tomorrow.

awesome..just putting this up here..think it's right...double check me...second Tee may be in the wrong place in the last diagram.

 

[shurur]

 

[ShadowDrake]

Gotchya. The first one is exactly how I have my setup done right now.

For reference.

I am wondering though - why was I seeing the hose between the thermostat housing and block (oil cooler - I am using the 2v block adapter which does not use the oil cooler because there is no space for the exhaust) collapse with revs? I guess it seems like it makes sense but I got the bad feeling that my coolant flow is in reverse but I don't think there's any way that is possible.

I'll double check the flow in the crossover plug when it's running - should be running left to right with the thermostat closed, and right to left with the thermostat open... Yes?

 

[shurur]

Gotchya. The first one is exactly how I have my setup done right now.

I am wondering though - why was I seeing the hose between the thermostat housing and block (oil cooler - I am using the 2v block adapter which does not use the oil cooler because there is no space for the exhaust) collapse with revs? I guess it seems like it makes sense but I got the bad feeling that my coolant flow is in reverse but I don't think there's any way that is possible.

I'll double check the flow in the crossover plug when it's running - should be running left to right with the thermostat closed, and right to left with the thermostat open... Yes?

That drawing is the modular without the head coolant mod.

Yes I guess your thermostat is housed in the block on top and directs coolant from the front of the heads (the hottest coolant) to the radiator..or when closed keeps the coolant circulating around the engine.

The oil cooler I mention is just the oil filter adapter inside the block to cool the oil filter (sorry).

Q: So you don't have a separate thermostat housing in your system? (The t-stat with housing actually hangs suspended by the radiator hosing as in the diagram on the 4v modular.)

Q:And You have put in a new bypass tube from the front of the heads (front freeze plugs) routed down to the lower radiator hose inlet to the lower block?

Either way..I believe you want those back head freeze plug connections feed back to a top radiator Tee.

Napa part 1-1/2 x 5/8 Tee 660-1742

But you may not need that outer bypass tube...that may be part of the overheating problem..where the coolant goes from the front of the heads needs to be regulated by the position of the t-stat.......I need to read your posts again.

For me: We need to get to the point of diagram for what you have.

right now I think (guessing) that your closed loop path is internalized to your motor on the 2V block..the bypass tube and the t-stat housing and ( expansion tank connection?).

 

[shurur]

That drawing is the modular without the head coolant mod.

Yes I guess your thermostat is housed in the block on top and directs coolant from the front of the heads (the hottest coolant) to the radiator..or when closed keeps the coolant circulating around the engine.

The oil cooler I mention is just the oil filter adapter inside the block to cool the oil filter (sorry).

Q: So you don't have a separate thermostat housing in your system? (The t-stat with housing actually hangs suspended by the radiator hosing as in the diagram on the 4v modular.)

Q:And You have put in a new bypass tube from the front of the heads (front freeze plugs) routed down to the lower radiator hose inlet to the lower block?

Either way..I believe you want those back head freeze plug connections feed back to a top radiator Tee.

Napa part 1-1/2 x 5/8 Tee 660-1742

But you may not need that outer bypass tube...that may be part of the overheating problem..where the coolant goes from the front of the heads needs to be regulated by the position of the t-stat.......I need to read your posts again.

For me: We need to get to the point of diagram for what you have.

right now I think (guessing) that your closed loop path is internalized to your motor on the 2V block..the bypass tube and the t-stat housing and ( expansion tank connection?).

ok, I see you have the same cooling system as the DOHC...I was descibing a pushrod block system...:??:

 

[shurur]

Gotchya. The first one is exactly how I have my setup done right now.

For reference.


I'll double check the flow in the crossover plug when it's running - should be running left to right with the thermostat closed, and right to left with the thermostat open... Yes?

Yes I think I understand...yes..ah no... flowing down through the bypass tube with the t-stat closed..but maybe just less flowing (velocity-wise).... if at all...through the bypass tube from the heads when the t-stat is open and pressurized coolant is drawn by the pump into the radiator and back to itself via the lower radiator hose and the t-stat..

 

[ShadowDrake]

Yes I think I understand...yes..ah no... flowing down through the bypass tube with the t-stat closed..but maybe just less flowing (velocity-wise).... if at all...through the bypass tube from the heads when the t-stat is open and pressurized coolant is drawn by the pump into the radiator and back to itself via the lower radiator hose and the t-stat..

Okay. I'l be testing this in a few hours when the car cools off. Just got home from work. And probably adding some more coolant if it'll take it

And thermostat orientation? I have it in the way that makes the most sense but I don't understand how it would close off the bypass in this orientation.

I have the thermostat with the bottom facing block side. The bottom in this case would refer to the sprung washer essentially. The top seals off the lower radiator hose and degas bottle from the bypass loop.

Someone care to explain how that works? I thought when the thermostat opened, it prevented coolant from flowing through the bypass gradually. At full open the bypass should be totally blocked. Right?

 

[shurur]

Okay. I'l be testing this in a few hours when the car cools off. Just got home from work. And probably adding some more coolant if it'll take it

And thermostat orientation? I have it in the way that makes the most sense but I don't understand how it would close off the bypass in this orientation.

I have the thermostat with the bottom facing block side. The bottom in this case would refer to the sprung washer essentially. The top seals off the lower radiator hose and degas bottle from the bypass loop.

Someone care to explain how that works? I thought when the thermostat opened, it prevented coolant from flowing through the bypass gradually. At full open the bypass should be totally blocked. Right?

***************
T-stat orientation seems right in that the spring part is in the bypass path....thats what the manual shows.

I think the T-stat never totally blocks the bypass path and is like a mixer function...I don't see how the construction would allow for totally blocking the bypass path off...I don't even think the system would want that to happen...hammering like that.

Anyone?