As the title says. I have a custom flipped header tt kit and to run the stock one is just a lot of cluster down there. Also do i need a bypass? so when the thermostat is closed the pump can still circulate water. i was just going to cap off the driver side hose coming off the coolant cross over tube.
Can I run an inline thermostat in upper hose????????
- Thread starter cobra196
- Start date
Yes, a inline t-stat can be used in the upper hose and a bypass is not required but make sure the system is bled of air as the bypass helps do this also.
MMR
MMR
That's what the bypass is for, not just what it helps to do. It's required. If you don't use one, the system won't vent the trapped air and it will quickly build in excess of 16 psi, then push coolant right past the 16 psi cap.
OP you can drill a hole through your crossover tube cap and tee it into the factory vent line behind the cap, or buy one of the manufactured caps sold on here that come with an 1/8th pipe thread hole. They are really nice. Then you'll need a 1-1/8th" rubber freeze plug to cap the crossover tube line.
Curious how you heard about this mod because I've never seen it posted on here. Just finished doing it on my car the other day. I bought the Summitt billet inline thermostat housing, it's a nice piece.
Last edited:
^^^can you post pics of what you did?
Well for the record I learned it from another member here who said he dreamed it up so I was just curious. Dude's username is 98mark8lsc, I took the liberty of looking up his posts:
I was going to start a new write up thread about this but I think I've been on here for too long because I get lazy. But anyway, I feel like this might be the answer to the common overheat problem with 96's. I'm also thinking it has nothing to do with the condensors, regardless of fin count, but that it's just a design flaw from Ford that can rectified by placing the thermostat in the upper hose. By the way, do you have a GT lower radiator hose? You'll need one of those too. $25 bucks from Summit. The design flaw is basically that 1" or so line going from the crossover tube down, that's nothing but hot water being recirculated. Great for fast warmups, emissions, etc, but bad once you get going on a hot day. Half the water going into your engine at any given time is recirculated hot water that HASN'T been through the radiator. The other half is water that has. Technically you could consider it half of a cooling system. I haven't tested the theory as my crossover pipe is being powdercoated, but I will post up when I get it back and get the car out.
Sure.
I replaced this:
With this: (a 99-04 stang GT lower hose)
That black thing is the rubber freeze plug, $2, and you tighten that nut to make it expand inside the tube. Then it's blocked.
Housing: ($70 I think)
Vent line tee: (have that cap I talked about earlier and an elbow by now)
Oh and you know what else? This thing takes a standard Chevy thermostat. Guess how much standard Chevy thermostat's are? 12 dollars! I see 170 degree ones on here listed for 50 bucks! Ridiculous!
Thanks for the pics. I had been thinking of doing the exact same thing because I kept wondering how this cooling system worked and kept thinking that how water/coolant keeps being recirculated. I just never really found a thermostat housing to put inline on the top hose. Can I ask where you got it from?
I can see it removing clutter but am not sure how better cooling can be realized as mentioned in the quoted post. The stock Cobra stat not only works like any other, it also does another job. There is a spring loaded plate with a hole in it that allows bypass water to flow thru but when the stat opens to let radiator water thru, it blocks water flow from the bypass. Sure some may scoot by since the plate does not have a perfect seal but I've got to wonder much this matters since the coolant will flow the path of least resistance and the bulk will be going thru the rad now that the stat is opened.
One important thing that needs to be considered is that with a stat in the lower hose, it will regulate flow thru the radiator based on the temp of the cooled water. With a stat in the upper hose, it will regulate the rad coolant flow based on the hot water coming out of the motor.
For example, my car has a 180* stat in the lower hose. My coolant sensor is in the crossover pipe. It gets to 210 on the gauge so the coolant picks up about 30*F passing thru the motor.
If I put a 180* stat in an upper hose, my gauge which reads coolant temp just before the stat would most likely read very close to the stat rating. Of course my lower hose would be much cooler. If I moved my 180 stat out of the lower hose, in order to see the same hot running temp, I would need to install a 210 in the upper hose...... The point I'm trying to make is that that to maintain a desired cooling temp within the cooling jacket of the block, a 97 Cobra (with an OE lower hose stat design) would need a stat rated quite a bit lower than a 97 GT (stat in the manfold right at the upper hose).
In addition in my mind, I'd be very carefull with deleting the bypass. The bypass allows for some circulation from cold to the stat opening point. This helps keep the coolant in the motor at a consistant temperature. It also passes that coolant right by the stat in the lower hose. 2V motors and pushrod V8's put the stat in the intake manifold coolant passage. In both cases there is some water flow that moves past the stat so it can open on time.
I do not have experience with swapping stat locations and deleting the bypass, but I would think that by deleting the bypass and moving your stat away from the motor in the upper line, it is insulated from the engine coolant since you are simply blocking the line. The concern I would have is that the coolant in the block can become extremely hot well before the stat sees any of that temp required to open it. I would imagine that by drilling a series of holes around the outside of the stat would allow for some hot coolant from the engine to at least reach down the hose to the stat pill. Still I would imagine not as good as a design as the OE setup.
One important thing that needs to be considered is that with a stat in the lower hose, it will regulate flow thru the radiator based on the temp of the cooled water. With a stat in the upper hose, it will regulate the rad coolant flow based on the hot water coming out of the motor.
For example, my car has a 180* stat in the lower hose. My coolant sensor is in the crossover pipe. It gets to 210 on the gauge so the coolant picks up about 30*F passing thru the motor.
If I put a 180* stat in an upper hose, my gauge which reads coolant temp just before the stat would most likely read very close to the stat rating. Of course my lower hose would be much cooler. If I moved my 180 stat out of the lower hose, in order to see the same hot running temp, I would need to install a 210 in the upper hose...... The point I'm trying to make is that that to maintain a desired cooling temp within the cooling jacket of the block, a 97 Cobra (with an OE lower hose stat design) would need a stat rated quite a bit lower than a 97 GT (stat in the manfold right at the upper hose).
In addition in my mind, I'd be very carefull with deleting the bypass. The bypass allows for some circulation from cold to the stat opening point. This helps keep the coolant in the motor at a consistant temperature. It also passes that coolant right by the stat in the lower hose. 2V motors and pushrod V8's put the stat in the intake manifold coolant passage. In both cases there is some water flow that moves past the stat so it can open on time.
I do not have experience with swapping stat locations and deleting the bypass, but I would think that by deleting the bypass and moving your stat away from the motor in the upper line, it is insulated from the engine coolant since you are simply blocking the line. The concern I would have is that the coolant in the block can become extremely hot well before the stat sees any of that temp required to open it. I would imagine that by drilling a series of holes around the outside of the stat would allow for some hot coolant from the engine to at least reach down the hose to the stat pill. Still I would imagine not as good as a design as the OE setup.
Last edited:
here is my set up. the bypass in the original thermostat mixes hot water with cool water-runs hot. the only reason for the cooling set up was for emissions and faster warm up. but as most in hot climate experience over heating. here is my set up, it runs cool in 100 deg with a/c as the old way would over heat in 5 min.
Summit.
Maybe so, I haven't tested it's effectiveness yet. I did heat up a thermostat in boiling water, placed it in the housing, then poured the hot water into the crossover tube opening and plenty of water flowed past those 4 little holes.
I'm not sure if it matters whether your reading the cooled water and getting an idea of the cooling system's effectiveness, or reading the warmed water and getting an idea of what temperature your engine is actually running. If you desired the former, you could always relocate your temp sensor. I'll be checking mine with a thermometer to see what the temps are at both spots.
It designed to do that, for faster warmups/emissions. I'm just not worried about that.
How would capping the crossover isolate a thermostat in the upper hose? The coolant in the block goes directly into the crossover. Coolant goes from the crossover directly into the upper hose. Upper hose=thermostat.
I wasn't aware that crossover line was blocked by an open thermostat, but I do know it's a poor seal. I'm not so sure this is the end of the issue now, but I'll definitely post results.
Whatever you want. 160 or 180.
Moving the stat to the upper hose it what isolates it. I mentioned both because the new configuration discussed above moves the stat to the top and deletes the bypass.
My concern is the thermostat effectively blocks the upper hose while its closed. Even though the water pump wants to push water down that hose, it can't go anywhere and will take a while to get the temp down to that point unless you drill holes to get some flow thru.
I'm very interested in this as I was putting my hot side on the other day and can see where it's gonna be tight down there. Can someone post pics from underneath so I can see if it's worth it or not as far as freeing up space. That would be my only reason for doing it really.
your going to want to do it, if not i bet your car will get very hot very fast. as for people that wonder about its effectiveness and operation ask yourself why in the gt500 did they get rid of the bypass and go to thermostat in the upper hose with air bleed lines to the tank....hmmm better cooling. as for your temp reading it will not be any different just because of the relocated thermostat.
Not to be argumentative but the GT500 does indeed have the stat away from the engine in the upper hose, but it still has a bypass. If you just look at it from the top it looks like a simple Y with two upper hoses going to a stat then to the radiator. But take a deeper look and you'll see there are 2 additional hoses coming out of the stat housing. A total of 5. The extras allow some coolant to flow thru the housing when the stat is closed.
There it is behind the tank.
Heres another shot
And, if you look at what a GT500 stat looks like.....
It looks very similar to ours with a bypass plate on the ass end. The system is very close to ours with a divorced stat housing but the GT500 has it up in the top hose, we have ours down low.
In both cases, and other OE situations its important to have positive cooling flow by the thermostat pellet so that it properly senses the water temp circulating just through the block and opens when is should to prevent whats in the engine from overheating.
Again, Perhaps drilled holes may be enough, it will slow warm up time but maybe a small price to pay. If your power adder requires it then I would just be carefull otherwise I wouldn't fool with it. Overheated water boils, fills your system with air. Lots of people do the cooling mod to get better water flow near 7&8. Rearranging the cooling system is a much bigger deal.
In addition, I think there is lots of confusion surrounding the unconventional T-stat location our cars have. Lots of us in our gearhead lives are very used to a manifold located stat at the engine coolant outlet and have a rough idea of what temp stat would be best for performance. But not everybody realizes that the location of the system greatly affects what temp stat you should choose.
The conventional manifold/top hose mounted stat reacts water at its hottest point, just as it leaves the motor on the way to be cooled down. The OE system in our cars reacts to water temp at its coolest point, out the radiator, on its way to be heated up again. Vastly different.
So, many people think since it was common to put a 180 or so stat in the old pushrod motors that a 180 is appropriate for the lower hose of a DOHC motor when it truth to end up with the same engine temp as you would with a 180 degree in the upper you need to go much lower. Some people say a 160 is too low, but is it?
My car runs at 210 or so based on the autometer elec gauge with a sender is in the crossover. I have a 180 degree Termi stat in the OE location. Initially I thought due to the big temp difference, my cooling system was not up to par. While this would have been true diagnosis with an upper mounted stat, after I thought about it, the 30 degree difference is reasonable considering water regulated to 180 degrees then passes thru a hot motor before I read its temp.
I guarantee that the water going into the motor is rock steady at 180 even though my gauge reads 210. One day I am going to borrow an IR temp gauge and verify this.
The conventional manifold/top hose mounted stat reacts water at its hottest point, just as it leaves the motor on the way to be cooled down. The OE system in our cars reacts to water temp at its coolest point, out the radiator, on its way to be heated up again. Vastly different.
So, many people think since it was common to put a 180 or so stat in the old pushrod motors that a 180 is appropriate for the lower hose of a DOHC motor when it truth to end up with the same engine temp as you would with a 180 degree in the upper you need to go much lower. Some people say a 160 is too low, but is it?
My car runs at 210 or so based on the autometer elec gauge with a sender is in the crossover. I have a 180 degree Termi stat in the OE location. Initially I thought due to the big temp difference, my cooling system was not up to par. While this would have been true diagnosis with an upper mounted stat, after I thought about it, the 30 degree difference is reasonable considering water regulated to 180 degrees then passes thru a hot motor before I read its temp.
I guarantee that the water going into the motor is rock steady at 180 even though my gauge reads 210. One day I am going to borrow an IR temp gauge and verify this.
Last edited:
I have my coolant temp gauge reading from this location:
See the wire coming down the backside of the block? See the sensor tapped into the block?
Anyhow.....I have a stock thermostat. When my readings at my coolant crossover are 210-215 degrees, the reading from this location shows 190-195.
Hope that helps!
Edit: Yes those headers are facing the wrong way. Turbo build in progress.
See the wire coming down the backside of the block? See the sensor tapped into the block?
Anyhow.....I have a stock thermostat. When my readings at my coolant crossover are 210-215 degrees, the reading from this location shows 190-195.
Hope that helps!
Edit: Yes those headers are facing the wrong way. Turbo build in progress.
So you are saying to run a vent tube from the fill cap on the crossover, to the stock vent line (tee it in) ?
A: What exactly is this for? Releasing trapped air?
B: The pictures posted, of the plugs with the fitting/tapped hole on top.....where do I get one of those? Please let me know asap.
C: When you say "manufactured caps sold on here".....are you referring to the ones you pictured, or expansion tank caps? Please post a link or show where to purchase.
After you answer these, I will go and get this done.
Thanks for your time.
Users who are viewing this thread
