If you have the factory cross over tube like I do straight fittings won't work. I have a 45 I think on pass side and a 180 on driver's.
Coolant system redesign/OEM style overflow tank elimination
- Thread starter JCDriller
- Start date
If you have the factory cross over tube like I do straight fittings won't work. I have a 45 I think on pass side and a 180 on driver's.
I have an On3 crossover delete I'll be installing. I think I should be fine I just don't know for sure
That is perfection! What did you have to do on the electrical side to have the mk8 fan? Did you just use a relay (maybe solid state?) and factory wiring as a trigger??
How about the lower hose, is the oil cooler still there?
I’m loving the safety and comfort my LPM is providing, thank you again for a wonderful product and for the support while I was getting it running.
The Mark 8 fan actually runs on the factory wiring and CCRM. I do activate the low speed and high speed relay's together to share the load.
Yes oil cooler is still there. I used a one piece lower radiator hose that goes from the radiator to the cooler. I did put a tee in there and connect to the bottom of my expansion tank.
No problem on the support and LPM.
With what you're proposing, with the fox or SN radiator, you'll still want or need a fill port on the highest point of the system. In that case you're better off from a functionality standpoint to have a pressure cap at the highest point so that it doubles as both a fill port as well as pressure cap, and reduces the amount of coolant for it to purge and recover during heat cycles.
For the bypass lines I don't know how I feel about just pulling off the rear cylinder heads without flow mapping done, but that's anyone's guess. I necked down my bypass to 3/4" (while still running the head cooling mod) and it's performed well.
Switching the thermostat to the engine out hose is a game changer though. My system deaerates so fast now. Lower hose thermostats are supposed to provide a more stable temperature to the engine, but they often have issues with fill and opening at the right temperature.
Now I know I'm standing alone here, but I would strongly reconsider completely deleting the surge tank. There's a big difference in recovery style (no surge tank, like the old foxes with a puke tank) and surge tank systems. The problem with recovery style is that it doesn't maintain pressure as well. You make a hard run, get it hot and it pushes coolant into the recovery bottle to maintain cap pressure. Now as soon as you let out and it starts to cool, it will start to pull vacuum at water pump inlet, and can cavitate. What the surge tank does is maintain a steady pressure- that trapped air gets squeezed and helps maintain pressure on the pump inlet. What I would recommend doing is retaining a surge tank in some fashion, even if it's a universal bottle and/or tucked away somewhere. I'm running a 1qt universal aluminum surge tank on mine where the PS reservoir usually is. You basically fill it like the stock system- fill from the highest point with all caps open, once it gets to the desired level in the surge tank, cap that and fill the rest of the way. You can even go with a sealed surge tank if designed properly. You want to target around 10-20% of system volume as "expansion space" or trapped air in that surge tank. That allows for coolant expansion without puking, but maintains pressure on the pump to prevent cavitation. I say this as someone who designs/tests OEM cooling systems.
For the bypass lines I don't know how I feel about just pulling off the rear cylinder heads without flow mapping done, but that's anyone's guess. I necked down my bypass to 3/4" (while still running the head cooling mod) and it's performed well.
Switching the thermostat to the engine out hose is a game changer though. My system deaerates so fast now. Lower hose thermostats are supposed to provide a more stable temperature to the engine, but they often have issues with fill and opening at the right temperature.
Now I know I'm standing alone here, but I would strongly reconsider completely deleting the surge tank. There's a big difference in recovery style (no surge tank, like the old foxes with a puke tank) and surge tank systems. The problem with recovery style is that it doesn't maintain pressure as well. You make a hard run, get it hot and it pushes coolant into the recovery bottle to maintain cap pressure. Now as soon as you let out and it starts to cool, it will start to pull vacuum at water pump inlet, and can cavitate. What the surge tank does is maintain a steady pressure- that trapped air gets squeezed and helps maintain pressure on the pump inlet. What I would recommend doing is retaining a surge tank in some fashion, even if it's a universal bottle and/or tucked away somewhere. I'm running a 1qt universal aluminum surge tank on mine where the PS reservoir usually is. You basically fill it like the stock system- fill from the highest point with all caps open, once it gets to the desired level in the surge tank, cap that and fill the rest of the way. You can even go with a sealed surge tank if designed properly. You want to target around 10-20% of system volume as "expansion space" or trapped air in that surge tank. That allows for coolant expansion without puking, but maintains pressure on the pump to prevent cavitation. I say this as someone who designs/tests OEM cooling systems.
Ok my friend you clearly understand the better than me, but I think we are already on the same page, please correct me if I'm wrong. Also, thank you for your input, I appreciate you taking the time to help.
My plan isn't to eliminate the surge/expansion tank, it's to hide it in a fender or at a minimum move it like 94slowbra1 or Malcom8 to open up the front of the engine for esthetics, cooling, ease of maintenance, etc. I'm going to use the SN95 radiator's fill port at a convenient and clean looking way to fill the system since my expansion tank will be hard to get to. I'm also accepting that I'll have to fill the system on ramps or a steep hill to get the fill port above the rest of the cooling system.
I won't need a pressure cap with the pressurized expansion tank, correct?, therefore I can weld up the barbed overflow tank output on the fill neck.
Bypassing off the rear drivers side head seems to be the norm for these types of mods, the passengers side passes through the heater core and using a line off the head near cyl 7/8 gives the otherwise trapped/slow flowing coolant a better way to escape and it helps open the thermostat (I know you already know that, just stating it to make sure I have it right) I don't see how this could be a problem and I'd imagine it flows better than trying to direct all the fluid in to the heater core like on the traditional head cooling mod. I ordered a Cobra Engineering cross over delete today so I'll be a -10an bypass off the rear drivers side head to the thermostat housing.
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So the mark 8 fan is pretty much plug and play no special wiring, Did you tap the the output of the slow speed relay to also kick on the high speed or was it done some other way? These fans aren't too expensive, it may be a nice upgrade to do at the same time as the rest of the system.
Also, what tanks are you running for your PS and overflow?
Finally, how's your car in Florida without AC? I assume you pulled it as I don't see any lines, or did you somehow tuck the AC lines?
Thanks again!
My friend never had any cooling issues at all with his setup and all he had was the sn95 radiator & a overflow catch bottle where the battery use to be. I think I'm gonna start with what he did and if I'm having issues I'll revisit it.
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The problem with that is that it isn't your highest point. You would want/need one at the crossover (or the equivalent for your setup.) That's going to lead to a sizeable unfilled portion.
If you wanted a really trick feature you could set it up with a vent and fill fitting. Put a small -4 size vent on your highest point (maybe one of the head outlets if you're using one of the AN adapter blocks) you could open during fill, and either put another small fill fitting on the other side or put a compucheck down low on the engine inlet that would let you pressure fill the system. Then you could just fill it hat way, and actually get a really good fill. A lot of OEM systems are configured that way.
Truth be told if I was more motivated I would put a compucheck fitting on my lower pipe and drain/fill the whole system from there. Just open my crossover plug, pressure fill it from the compucheck, and I wouldn't even need to deaerate/burp it.
If you have a pressure cap elsewhere in the system, you would not need a pressure cap on the expansion tank- you would need something that seals to a higher pressure than the pressure cap of the system. Basically it wouldn't regulate system pressure, and wouldn't need the outlet barb for venting. (Though two pressure cap systems are another design possibility and have some other considerations...)
However make sure wherever you do have the pressure cap you do have an outlet barb on it.
The concern there is how you're changing it from the stock configuration. With yours, when the thermostat is closed, the only outlet is the bypass out the back of the heads. In essence you could be creating the same problem with stagnating flow, but at the front of the head this time, at least during closed thermostat. Remember with the head cooling mod and the stock bypass it allows flow out of both the front and the rear of the head even with the thermostat closed. Yours would only allow the rear.
Out of curiosity what exact compucheck fitting would you use? And it would be plumbed into the lower hose?
@SecondhandSnake I REALLY appreciate your input. I put my comments in red. Thank you again.
The problem with that is that it isn't your highest point. You would want/need one at the crossover (or the equivalent for your setup.) That's going to lead to a sizeable unfilled portion.
Would this be a problem if the system was filled while the car was on ramps so that it was the highest point? Would air somehow find its way back in?
If you wanted a really trick feature you could set it up with a vent and fill fitting. Put a small -4 size vent on your highest point (maybe one of the head outlets if you're using one of the AN adapter blocks) you could open during fill, and either put another small fill fitting on the other side or put a compucheck down low on the engine inlet that would let you pressure fill the system. Then you could just fill it hat way, and actually get a really good fill. A lot of OEM systems are configured that way.
Truth be told if I was more motivated I would put a compucheck fitting on my lower pipe and drain/fill the whole system from there. Just open my crossover plug, pressure fill it from the compucheck, and I wouldn't even need to deaerate/burp it.
I just rewatched the video on the Cobra Engineering Cross Over delete. It looks like he included a fill port in the drivers side cross over adapter. I'll email him to verify that is what it is, but I think this makes filling the system a snap.
If you have a pressure cap elsewhere in the system, you would not need a pressure cap on the expansion tank- you would need something that seals to a higher pressure than the pressure cap of the system. Basically it wouldn't regulate system pressure, and wouldn't need the outlet barb for venting. (Though two pressure cap systems are another design possibility and have some other considerations...)
However make sure wherever you do have the pressure cap you do have an outlet barb on it.
If I put a 16psi pressure cap on the SN95 radiator and I kept a expansion tank that was sealed (no pressure cap) in the fender coming off the lower radiator hose would I then also need an overflow tank hooked up to that outlet barb?
The concern there is how you're changing it from the stock configuration. With yours, when the thermostat is closed, the only outlet is the bypass out the back of the heads. In essence you could be creating the same problem with stagnating flow, but at the front of the head this time, at least during closed thermostat. Remember with the head cooling mod and the stock bypass it allows flow out of both the front and the rear of the head even with the thermostat closed. Yours would only allow the rear.
I'm following you now, I can see how until the thermostat opens nothing is flowing off the front of the heads. going back to the cobra engineering photo above there is a second threaded port in the passengers side adapter that is for additional sensors if needed. I could make that a bypass too, ting the rear drivers side head into the front passengers side head then to the thermostat. this would at least give some flow out of the front of the heads. Thoughts on this approach
The problem with that is that it isn't your highest point. You would want/need one at the crossover (or the equivalent for your setup.) That's going to lead to a sizeable unfilled portion.
Would this be a problem if the system was filled while the car was on ramps so that it was the highest point? Would air somehow find its way back in?
If you wanted a really trick feature you could set it up with a vent and fill fitting. Put a small -4 size vent on your highest point (maybe one of the head outlets if you're using one of the AN adapter blocks) you could open during fill, and either put another small fill fitting on the other side or put a compucheck down low on the engine inlet that would let you pressure fill the system. Then you could just fill it hat way, and actually get a really good fill. A lot of OEM systems are configured that way.
Truth be told if I was more motivated I would put a compucheck fitting on my lower pipe and drain/fill the whole system from there. Just open my crossover plug, pressure fill it from the compucheck, and I wouldn't even need to deaerate/burp it.
I just rewatched the video on the Cobra Engineering Cross Over delete. It looks like he included a fill port in the drivers side cross over adapter. I'll email him to verify that is what it is, but I think this makes filling the system a snap.
If you have a pressure cap elsewhere in the system, you would not need a pressure cap on the expansion tank- you would need something that seals to a higher pressure than the pressure cap of the system. Basically it wouldn't regulate system pressure, and wouldn't need the outlet barb for venting. (Though two pressure cap systems are another design possibility and have some other considerations...)
However make sure wherever you do have the pressure cap you do have an outlet barb on it.
If I put a 16psi pressure cap on the SN95 radiator and I kept a expansion tank that was sealed (no pressure cap) in the fender coming off the lower radiator hose would I then also need an overflow tank hooked up to that outlet barb?
The concern there is how you're changing it from the stock configuration. With yours, when the thermostat is closed, the only outlet is the bypass out the back of the heads. In essence you could be creating the same problem with stagnating flow, but at the front of the head this time, at least during closed thermostat. Remember with the head cooling mod and the stock bypass it allows flow out of both the front and the rear of the head even with the thermostat closed. Yours would only allow the rear.
I'm following you now, I can see how until the thermostat opens nothing is flowing off the front of the heads. going back to the cobra engineering photo above there is a second threaded port in the passengers side adapter that is for additional sensors if needed. I could make that a bypass too, ting the rear drivers side head into the front passengers side head then to the thermostat. this would at least give some flow out of the front of the heads. Thoughts on this approach
Well I wouldn't say plug and play. You need to swap electrical connectors so it'll plug in and you need to trim the housing and make some mods for it to fit. I have write up on my website, or STVP or both actually I think.
As for triggering it, pretty easy if you follow the wiring diagrams, mine's a little custom as I'm using the MS3Pro ECU and it controls the fans now via the CCRM.
I removed AC since the bulk of the year its not really needed when out having fun and honestly in the 16+ years I've owned the car I barely ever used it. If it's mid summer mid day heat I have a coyote car with AC I'll use.
The tanks are custom, welded up from Aluminum. The PS one I made from scratch, if you do the same be sure and baffle accordingly. Lots of info on a google search on how to properly baffle one. The expansion tank I started with something I had laying around and modded for my application.
Off topic, but are you kidding me? You live in Tampa now? Tell me this is true and not some sick joke, please! Pm me your number if so please.
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Technically that would be ok, but that would have to be one hell of an incline. I mean you could fill your oil from the drain plug by flipping the car upside down but it isn't very convenient.
That certainly makes it easy.
I think you'd still need one off the radiator neck, but not the sealed expansion tank.
The thought/issue there is that with the cap on the radiator like that, during normal operation it's going to act like the old foxes as far as venting/recovery goes. When your system hits that 16psi, the cap is going to lift to relieve that pressure. Since it isn't the highest point in the system, that portion should be full of coolant. That means it's going to release coolant instead of air/vapor. That's fine and dandy for the foxes because that's how they're set up with the recovery tank. Here it's fine, but it's still added complexity.
With a surge tank you ideally want the cap atop an air pocket so that it vents air/vapor. If you look at the stock one, that's how it's set up.
Given the outlet blocks have a fill port, if anything I would recommend running it more or less like I have it, which is still similar to stock. Use a universal surge tank with a pressure cap (Speedway has some nice ones) and hide it wherever you want. Fill the system until you reach the desired level of trapped air in it, then cap it. Then fill the system the rest of the way. You'll leave the barb on the surge tank, but it's going to be venting/pulling in air, not coolant.
If it's an 1/8" NPT it might be too small, but I suppose anything is better than nothing. 1/4" NPT would probably be better. With the bypass just make sure it goes to water pump inlet, whether that's via the lower block inlet or the valley heater core line.
Forgot to mention the compucheck fittings, although I think that might be a trade name. You should be able to get them from your average hose and fitting shop. I think Parker has them labeled as "test port and diagnostic quick couplings." Either 1/8" or 1/4" NPT ones will be fine, depending on how fast you want to fill. 1/4" is suitable for heavy trucks, so take that for what it's worth.
For installation location if you put it in the lower radiator hose/pipe, or hell, even in place of the draincock, the big advantage is that it makes it so much quicker and easier to fill and drain. You can use a vacuum rig to pull the coolant out quicker. When you fill it, you're filling from the lowest point so it fills quicker and there's less air to have to burp out of it when you're done.
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@SecondhandSnake
Ok, I'm starting to understand this stuff a bit better. Now that I know I have a fill port in the Cobra Engineering Cross over delete adapter, is there ANY reason to go to a SN95 radiator with the fill port? If there is no benefit, I'll return it and keep my cobra radiator stock or maybe upgrade to a 03/04 Fluidyne.
Sounds like my best solution is a simpler one.
Cobra engineering cross over delete
04 style radiator
Cobra Engineering oil cooler delete (GT lower hose with T going to expansion tank in fender)
universal expansion tank in the fender with a 16psi pressure cap (leave air bubble)
Replace draincock with compucheck fitting
fill system via vacuum at CE cross over delete adapter fill port and pull coolant through the compucheck fitting.
How do I keep the air in the expansion tank when I fill using vacuum?
Thank you!
Ok, I'm starting to understand this stuff a bit better. Now that I know I have a fill port in the Cobra Engineering Cross over delete adapter, is there ANY reason to go to a SN95 radiator with the fill port? If there is no benefit, I'll return it and keep my cobra radiator stock or maybe upgrade to a 03/04 Fluidyne.
Sounds like my best solution is a simpler one.
Cobra engineering cross over delete
04 style radiator
Cobra Engineering oil cooler delete (GT lower hose with T going to expansion tank in fender)
universal expansion tank in the fender with a 16psi pressure cap (leave air bubble)
Replace draincock with compucheck fitting
fill system via vacuum at CE cross over delete adapter fill port and pull coolant through the compucheck fitting.
How do I keep the air in the expansion tank when I fill using vacuum?
Thank you!
Yeah there's no real need for the fox/SN radiator with a fill cap. If you wanted to run one for some reason, you'd want to run it with a higher pressure cap than your expansion tank, more or less so it doesn't actuate. I'm doing that with my Subi radiator that I had to run for the center inlet out of necessity.
But basically just think of it as running a stock style system, just with a thermostat relocation and expansion tank relocation.
Fill it the same way you would the stock one. Open up your crossover and expansion cap. Hook up your pressure fill system to the draincock/compucheck fitting. Push coolant into the system until it reaches what becomes your new "fill cold" line on the new expansion tank. You should try to leave approximately 10-20% of the system's total volume empty in it. (Ex: 10qt system. Stop filling when there's 1-2qts of the expansion tank unfilled.) Now cap off the expansion tank. Continue filling until you see it up to the fill plug. Close the fill plug.
Now for the deaeration (burping) process. I've tried doing it the Ford recommended way with the funnel in the crossover. But it tends to make more of a mess than it's worth, and provided you didn't do anything too crazy to goof it up, you can just heat cycle it a time or two and then top it off from the crossover plug. I barely need to top mine off, and that's with a top fill, not a pressure fill.
But basically just think of it as running a stock style system, just with a thermostat relocation and expansion tank relocation.
Fill it the same way you would the stock one. Open up your crossover and expansion cap. Hook up your pressure fill system to the draincock/compucheck fitting. Push coolant into the system until it reaches what becomes your new "fill cold" line on the new expansion tank. You should try to leave approximately 10-20% of the system's total volume empty in it. (Ex: 10qt system. Stop filling when there's 1-2qts of the expansion tank unfilled.) Now cap off the expansion tank. Continue filling until you see it up to the fill plug. Close the fill plug.
Now for the deaeration (burping) process. I've tried doing it the Ford recommended way with the funnel in the crossover. But it tends to make more of a mess than it's worth, and provided you didn't do anything too crazy to goof it up, you can just heat cycle it a time or two and then top it off from the crossover plug. I barely need to top mine off, and that's with a top fill, not a pressure fill.
What lower hose did you use? Do you have a P/N?
I don't have a part #. I usually just go into the back of the auto parts store and browse their wall of hoses and find something that fits.
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