1994 6.5 water flow diagrams

[High Toned SOB]

Hi everyone, hope your all getting some wrenching done!!

I need a coolant system flow diagram for a 1994 k1500 automatic 6.5 truck. Preferably one in color so i can see direction of flow, heat exhange, etc...

I am trying to plumb in a water to air intercooler, and would like to ise the existing cooling system.

Thanks!

[sctrailrider]

Why in the world you do that, heating the air up defeats the purpose me thinks... a separate system is how they are designed, that way you are circulating cool water, not hot water...


But if you must, google has lots of diagrams for our motors water flow..

[High Toned SOB]

Why in the world you do that, heating the air up defeats the purpose me thinks... a separate system is how they are designed, that way you are circulating cool water, not hot water...


But if you must, google has lots of diagrams for our motors water flow..

Sctrailrider....with all due reapect even though i dont know you from adam....the fact that you spent the time to reply nothing...of course i know i dont want to preheat the air.... i know you are a veteran on the boards. I have seen your name ALOT. I want a diagram to see the flow direction, so i can see where it would be the coldest, then i could plumb that into the heat exchanger for more of a reduction before the actual intercooler. Right now i have a top mount air to air, looking for more as usual, lol.

If its coming out of the radiator at the top passenger side hose at 160*, then i go into my exchanger and out at 120*, then i win. But i need to know flow direction and heat/cooling exchange pattern first.

Please dont post unless its useful, thats like telling someone to google it when they just want to be a prick and not answer with knowledge they already have. I have already googled and only came up with humvees, which i clearly dont have.

Thanks,
94 k1500 6.5

[sctrailrider]

OK, common sense would say out the bottom of the radiator would be the coolest as for the flow, not many ways to figure it, the water flows in the top and out the bottom of the radiator...

[JohnC]

No offense meant, OP;I understand what SC Trailrider is saying, but I don't understand what you're saying (or asking). It sounds like you are saying you can use 160 degree water to cool something to 120 degrees. Can't imagine how you are going to do that.

The Humvee engine is the same; the water flow through the engine is the same, too.

[56pan]

I've got an aftermarket turbo on my '93. Mech. inj. pump, no wastegate. I installed a Peninsular Diesel intercooler about 3 yrs. ago. I also installed a Glowshift dual temp. gauge that shows the temp. of the air leaving the turbo compressor about 5 inches from the compressor outlet, and also shows engine inlet temp. (after the intercooler) about 6 inches before the air enters the intake manifold. When I've got my foot in it, on a hot day in NC (probably 90-94 F. ambient) I'll get a max. of approx. 210 F. out of the compressor and a max. of about 120 F. at the engine inlet. I never run more than about 13 psi. boost. I want this engine to live a long time. Do the math. What's the coldest coolant temp. you could get from the engine's cooling system? Look at the temp. differential between that temp. and the compressor outlet temp. You_have_to have a higher differential temp. than that. In my opinion, you're wasting your time. You'll need a separate radiator for the cooling system on your water to air intercooler. It's been done and works. SCTrailrider is right.

[DmaxMaverick]

I think I understand what you want to do. The coolest coolant will be from the radiator outlet. However, you do not want to just plumb from there, for the intercooler. You can pull coolant from there, but you'll need a secondary pump to move the coolant to the heat exchanger, then to the intercooler, and return it to the radiator inlet.

You must have a secondary pump (electric, belt driven, etc.) to move the coolant through an independent I/C loop, for a couple reasons. There will be no usable coolant flow when the thermostat is closed, and too little at partial opening, and the coolant must be returned to the radiator inlet before cycling through the engine.

If your cooling system is healthy, look for a significantly lower temp than 160F at the outlet. Probably closer to 120F (average conditions), but that depends on many factors, including ambient temps.

That said, a completely independent I/C system wouldn't be much different than that, and one leak won't take down both systems, or worse.

[High Toned SOB]

Ok, maybe im not being clear. Let me break this down, i hate not being able to actually talk face to face...

I want to find the coldest, yet pressurized part of the factory cooling system, so i can take off from there, into a hose to my heat exchanger, then into the intercooler, out of that back into the factory cooling system, hopefully on the suction (or non-pressure) side now.

The humvee i found on google does not have the same style cooling as my truck. I have like currently 3 gmt400’s with the 6.2/6.5, not to mention all the square body’s from the past, blah blah.
The hummer setup “i found”, does not have the same hose routing diagram as mine.

I just want a diagram of the complete cooling system, so i can see what direction the coolant is traveling, and when it should be at its hottest or coldest.

More importantly, the hose from the radiator to the coolant tank on the top passenger side, what does it do? Seems to stay cool for the most part, even when the others are hot. I took it off, coolant sprays from the radiator, but im not sure if there is enough pressure there to feed into my heat exchanger, then to the intercooler, and back to maybe the water pump suction side?

Basically i am just trying to use the factory cooling systems “water and pump” for the new water to air system. To me, it makes sense to pull water from the coldest part of the factory system into my heat exchanger (cooling it even more), then into the intercooler.
Am i right or way off base? Any other platform and its just air to air, but this truck’s air-to air system is very much bulky and in the way.

[56pan]

[QUOTE=DmaxMaverick;328372] (snipped)

You must have a secondary pump (electric, belt driven, etc.) to move the coolant through an independent I/C loop, for a couple reasons. (snipped).

No. Only for one reason. He will_not_be able to get coolant from the engine cooling system from any location that work efficiently in an air to water intercooler. He will have to use a separate cooling system and radiator to make this work.

[DmaxMaverick]

[QUOTE=DmaxMaverick;328372] (snipped)

You must have a secondary pump (electric, belt driven, etc.) to move the coolant through an independent I/C loop, for a couple reasons. (snipped).

No. Only for one reason. He will_not_be able to get coolant from the engine cooling system from any location that work efficiently in an air to water intercooler. He will have to use a separate cooling system and radiator to make this work.

Normally, I would agree. But, he seems intent on using the existing cooling system. I offered a solution that would have some benefit, being, the heat exchanger. Using hot engine coolant, before passing through the radiator, will see no benefit. It will just be sending hot coolant through another (much smaller) radiator with much less cooling efficiency than the original. 160F to 120F is possible with an efficiently sized and located heat exchanger, but unlikely. More like 200F to 160F during real world use.

[56pan]

[QUOTE=56pan;328374]

Normally, I would agree. But, he seems intent on using the existing cooling system. I offered a solution that would have some benefit, being, the heat exchanger. Using hot engine coolant, before passing through the radiator, will see no benefit. It will just be sending hot coolant through another (much smaller) radiator with much less cooling efficiency than the original. 160F to 120F is possible with an efficiently sized and located heat exchanger, but unlikely. More like 200F to 160F during real world use.

I understand what you're saying, sir. But I just cannot see this working at any efficiency that would do any good. Again, just my .02 and seeing what differential temps. I'm seeing in/out of an air/air intercooler. You have to have a cooling source of significantly less temp. than the temp. of the compressor discharge. The eng. cooling system is just not going to do it.

[sctrailrider]

More importantly, the hose from the radiator to the coolant tank on the top passenger side, what does it do?


That would be the overflow tube, it is on the outside of the system and fluid only moves through it when the cap releases pressure.

[sctrailrider]

Here ya go, a link to every known manual for the 94 .... cooling is section 6.. download them ..



https://www.dieselplace.com/forum/63-gm-diesel-engines/21-6-5l-diesel-engine/53309-6-5l-faq-s-master-list-information-6-5-answers.html#post7233722

[JohnC]

There is no high pressure side and suction side. The whole system is pressurized. The pump causes flow without much of a pressure differential, much like a home forced hot water heating system. When you add a new loop you need another pump.

There are venturi devices used in home heating to feed secondary loops without a pump that you might be able to make work, but I'd be concerned about reducing the cooling system capacity for the engine.

As others have stated, there is no flow through the radiator when the thermostat isn't open, anyhow. Likewise, the reason the hose to the tank is cool is that there is virtually no flow there. Start it flowing and it'll get hot quickly.

[High Toned SOB]

Wow thank you that will come in handy for diagnosing electrical..
However i still cant find any diagrams of coolant flow direction. 6B1-12 starts the diesel part, but it doesnt really tell you like ;
“so the water pump pulls from the radiator, and pushes through the block, upwards through the heads, and back up to the tstat housing. Until the tstat opens, the water is bypassed from the water pump back into the heads. Meanwhile, the flow is directed to the heater core from the tstat housing junk quick connect fitting, through the heater core, and into the right side tank of the radiator. While this is going on, the top 1/2” hose going to the surge tank is no flow. Then once the tstat opens, you get full flow through everything.......except on the 97 and newer models, they do this and that differently, BECAUSE they found there wasnt enough flow here and here”

Im sure alot of that is wrong, but you get what im saying.

If i cant get an actual diagram, then a detailed description would be great. Even if my idea doesnt work, thats fine, would still be nice to know. I mean, this is how we discovered the 4 corner cooling mods and such, and how the LSx’s became so good at cooling.

Thanks for the manual, thats awesome.

[High Toned SOB]

This hose right here, if i unhook it from the radiator, there is coolant flowing out of the radiator. So its almost like a recirculation hose back to the tank, then pulled down into the lower rad hose?

It seems to be the coldest, but i dont know if there would be enough flow volume to run through my heat exhanger to further cool it, then to the intercooler?

[High Toned SOB]

There is no high pressure side and suction side. The whole system is pressurized. The pump causes flow without much of a pressure differential, much like a home forced hot water heating system. When you add a new loop you need another pump.

There are venturi devices used in home heating to feed secondary loops without a pump that you might be able to make work, but I'd be concerned about reducing the cooling system capacity for the engine.

As others have stated, there is no flow through the radiator when the thermostat isn't open, anyhow. Likewise, the reason the hose to the tank is cool is that there is virtually no flow there. Start it flowing and it'll get hot quickly.

John i get how the system works when the tstat is closed. Well, not completely flow direction wise, but i understand the radiators function. What im saying, is even when the system is warm-ish 160*+, this small hose stays cool, compared to the heater core return hose right below it.
If i add another device into the cooling system, that doesnt automatically mean i need another pump. Depending on the load/size/distance, sure you “could” be right. But if i added a larger radiator, i wouldnt need another pump. If i added a heat exchanger 26x16x2, with 1/2 lines, thats not a whole lot of additional liquid. The factory wp could easily fill that and circulate, AS LONG AS i installed it in a pressure line. Like the heater core hoses. Im just trying to find the coolest pressurized circulating hose in the system.

This is not a drag car. I dont need a complete separate system with an ice box and a high special gpm electric pump. What does the factory pump flow? A bunch im sure. Enough to tap in another 10-12’ of 1/2” coiled hose. Right? Or wrong?

[Yukon6.2]

Hi
The hose in your picture is a make up hose.When the cooling system cools off the coolant shrinks and pulls coolant from the tank.When the coolant gets hot it expands and fills the tank.
Just for experimentation use the lines for your heater to try your theory.
When it doesn't work like you want you can return it back to stock and try an external water source and pump to get the results you want.
As mentioned before the cooling system in your truck is marginal at best when these trucks were new.Messing with the flow or changing the flow will not help your engine when you add more fuel and air to it,resulting in more heat for the cooling system to deal with.

[DmaxMaverick]

This hose right here, if i unhook it from the radiator, there is coolant flowing out of the radiator. So its almost like a recirculation hose back to the tank, then pulled down into the lower rad hose?

It seems to be the coldest, but i dont know if there would be enough flow volume to run through my heat exhanger to further cool it, then to the intercooler?

As said above, the coolant tank hose has ONLY static system pressure. Flow is only created when pressure at the outlet end (pressure cap) is lower than the general system pressure. There is no FLOW outside of that. The line does not circulate any fluid, it is only a termination. If the system is cold/cool, or once the pressure is balanced, there is no flow to be had or used. The same applies to the return line to the radiator.

The heater core loop is only that: a loop that circulates coolant from the engine outlet(s) to the heater core, and back to the cold side of the radiator. The reason for this is to get heat into the cabin as soon as is possible. This loop will be the only circuit with significant flow, but it's job is to carry heat out of the engine and into the cabin. It's a hot loop, so no good for anything outside of moving heat to a destination away from the engine.

As John said, there is no usable coolant flow outside the engine coolant closed loop. Taking flow away from the circuit will move hot coolant, and reduce the heat moved to the radiator. This may or may not be a benefit to the engine cooling, but it will dump all that heat into whatever you are exchanging. In your case, probably heating the charge air, rather than cooling it.

If you are a subscriber to any of the "bypass cooling mods", you really need to seek a better source of information. All of them are bunk. None of this will make sense until you do. All any of them do is reduce indicated heat, but none of them actually improve actual heat removal. In fact, they worsen the condition. The positive selling point is based on what a user may see on a temp gage, which is the indicator that less heat is being transferred to the coolant outlet. Contrary to popular belief among some circles, the best indicator of greater heat exchange is actually a HIGHER indication at the outlet. The engine will produce the same volume of heat under the same conditions. That's irrefutable fact. The difference with a bypass system is you are seeing a lower amount of heat being moved. That equates to more heat being retained in the engine.

[High Toned SOB]

Yukon and dmax, thats what i was looking for, something like the heater core loop i can just add to. But not that obviously.

What about the plugged port in the water pump? Thats suction right? So what if i pulled from the bottom radiator hose, into the exchanger, into the intercooler, then dumped right into the water pump?

I get what you guys are saying about the cooling systems limitations, and how its not designed to add on/etc etc.

But im not “really” adding more heat to the cooling system. I am trying to take from the coldest spot, cool it down even more, heat it back up some yes, but not even to engine operating temp, and return it to the cooling system.

So i dont understand how your saying its “adding” load to the cooling system.

Thats why i wanted a diagram of flow and heat exchange type stuff.

I have a thermal gun i am shootin temps with, so i can see the temp changes, but i still dont know the direction of flow/pressure/suction.

I also know earlier on someone said the system doesnt have pressure/suction. I dont see/understand how thats possible. We have the hotside that is pressurized by the water pump and increased by heat. Then we have the cooled side that is suction/pulled back into the water pump.
So since it is a loop, there has to be suction/pressure. Right?

Dmax, i am not a subscriber or whatever you meant to the cooling stuff, i dont totally know what your referring to. I was talking more about 4 corner cooling on gas stuff i have, i just ASSumed it would be the same concept on this v8. Im wrong then?

[High Toned SOB]

Also dmax you are saying the bypass stuff is NOT true? Where can i find this info to read it? I did find a guys website about how WMI is superior to intercooling, he has some hate speech in there about other guys, is that it?

Sorry i dont spend much time on the web, so i dont know all the different camps/good ol boys/clubs etc etc.
i just spend most extra time trying new things������������*♂️

[DmaxMaverick]

I wasn't presuming that you support or not, any of the theoretical cooling options available. Your posts were just taking the appearance that you might, and wanted to put that to sleep early. I wasn't referring to WMI. I'm a huge fan of that, and it works as advertised.

As John said earlier, the water pump won't push or pull volume at pressure enough, through any port or circuit, to do what you want, that won't upset the very delicate balance of engine cooling. The mention of the heater core loop was only an example, and would not be suitable for your intents, in any case. You won't find any circuit/port that will provide cooled coolant. It doesn't exist. Your coolant flow description in post #15 is pretty close to actual.

[arveetek]

I also know earlier on someone said the system doesnt have pressure/suction. I dont see/understand how thats possible. We have the hotside that is pressurized by the water pump and increased by heat. Then we have the cooled side that is suction/pulled back into the water pump.
So since it is a loop, there has to be suction/pressure. Right?

You're thinking in terms of a water system where a pump is pulling water from one source and pushing it into another, causing pressure. The cooling system on a vehicle, however, has nearly equal pressure on both sides of the pump. It's a completely closed system, there is no pressure from the pump. The water pump provides flow, but no pressure. It's simply moving the water around inside the closed system. That's why the thermostat can close and cut off the flow of water without causing damage to the system: there is no pressure, only flow.

The 6.5L diesel cooling system is marginal at best. Adding a water to air heat exchanger for the turbo utilizing the existing engine coolant is a bad idea, I'm afraid. Not only will you put a larger heat load on the engine coolant (even with an added small radiator), but you might even cripple current coolant flow and end up with hot spots in the engine. Your efforts will be better utilized using a separate coolant system for the turbo.

Casey

[phantom309]

In my opinion, every 6.5 i have seen with a larger turbo stays much cooler all around. Coolant temps, egt's, and iats',. Oil temps All lower.
Fuel mileage goes up too.
Jm2c

Ps don't ever discuss 4 corner cooling on this forum,..very closed minds here.