Hello, i am starting to have slight cooling issues after a hx35 swap and am looking for info. Not sure exactly what is the best route, and i do not want to throw tons of $ around at hypothetical fixes. Im running a hx35 set to about 12 psi max, my upper intake has wmi ports drilled, factory single t stat, pump and fan. Im aware of a couple of routes to go down, but am looking for any and all additional information and opinions. Thank you
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Best bang for buck 6.5 cooling upgrades
- Thread starter Jeepskate
- Start date
Will L.
Well-Known Member
Have you removed and cleaned the cooling stack? What fan and fan clutch are you running and how old is it?
What egt are you getting and where is the sensor located?
Balanced flow water pump, I believe your thermostat is a block off style, if so keep it, if not replace it for the block off one And run the AC Delco stat. Then for fan clutch and fan, look up the electro viscous set up done by @ak diesel driver. If you don't want the electro viscous, then Kennedy fan clutch.
Beyond that there is better radiators available, and thermal coating for the radiator.
Remember that 220 is where the cylinder walls shrink enough to start tightening on the rings, so keep it below there.
What egt are you getting and where is the sensor located?
Balanced flow water pump, I believe your thermostat is a block off style, if so keep it, if not replace it for the block off one And run the AC Delco stat. Then for fan clutch and fan, look up the electro viscous set up done by @ak diesel driver. If you don't want the electro viscous, then Kennedy fan clutch.
Beyond that there is better radiators available, and thermal coating for the radiator.
Remember that 220 is where the cylinder walls shrink enough to start tightening on the rings, so keep it below there.
Will,
Currently i am running it how is came from the p.o. He was very knowledgable with the 6.5's and had recently flushed the system. I was planning to remove, clean and replace the radiator when i did the harmonic balancer (waiting on puller/installer to arrive, delco pulley and balancer). I do not have an egt gauge, only aftermarket gauge is boost at the moment.
Have been collecting info for months now waiting for the cooling need to arise. Apparently hauling a small tractor on trailer +turbo swap was the kick I needed!
Currently i am running it how is came from the p.o. He was very knowledgable with the 6.5's and had recently flushed the system. I was planning to remove, clean and replace the radiator when i did the harmonic balancer (waiting on puller/installer to arrive, delco pulley and balancer). I do not have an egt gauge, only aftermarket gauge is boost at the moment.
Have been collecting info for months now waiting for the cooling need to arise. Apparently hauling a small tractor on trailer +turbo swap was the kick I needed!
If you replace the radiator I offer 3 row aluminum units that I apply a ceramic thermal dispersant coating to to enable 33% more heat dissipation than bare aluminum..
I was trying to find your site the other day for more info, came across your name on another site. I do not use facebook, makes things difficult sometimes. If the issue persists after the radiator cleaning i will give you a shout. Champions that you coat? Would be perfect, as they come uncoated and im in the midwest.
JMJNet
Recruit
You need to wash the outside, that is what they say about cleaning the cooling stack.
Cooling stack includes: radiator, AC condensor, oil cooler and trans cooler.
A lot of people flush the radiator but forgot to spray the radiator and other part of the cooling stack.
Best bang is to clean it first (outside not just a flush) and go from there.
Also make sure that the t-stat in there is ACDelco or RobertShaw.
Cooling stack includes: radiator, AC condensor, oil cooler and trans cooler.
A lot of people flush the radiator but forgot to spray the radiator and other part of the cooling stack.
Best bang is to clean it first (outside not just a flush) and go from there.
Also make sure that the t-stat in there is ACDelco or RobertShaw.
Pulling a bed full of elm temp spiked slightly, maybe 190, after being out of the boost. Gauge usually looks like the attached pic. On another note, is oil pressure normal? This is cruising in od, about 1500 rpm. Also attaching a pic of my coolant crossover.
Attachments
I don't have the web site any longer, here or twistedsteelperformance@gmail
ak diesel driver
6.5 driver
You actually have the rare and highly sought after by some tstat housing
Ooh, I like how that sounds! Is this typical of a certain year, or gvw rating?
ak diesel driver
6.5 driver
96 only, had the accessories on the opposite side as 95 and earlier (same as 97+) but only had a single tstat whereas 97+ had the dual stat
JayTheCPA
Well-Known Member
What are we defining as cooling issues? If the truck does not not bust temperature past 210* F, then all is good.
FWIW, the picture of the gauge cluster indicates the truck is a 96+. If so, consider getting an Edge monitor as it will provide coolant temperature as the computer sees it (from the sending unit at the crossover) versus the dash gauge which is not really accurate and gets its inputs from a sending unit in the head above #1.
In any event, one factor not touched on yet is the intake air. If the intake is getting air from inside the engine bay and not so much outside air, it will translate into hotter coolant when working the motor.
FWIW, the picture of the gauge cluster indicates the truck is a 96+. If so, consider getting an Edge monitor as it will provide coolant temperature as the computer sees it (from the sending unit at the crossover) versus the dash gauge which is not really accurate and gets its inputs from a sending unit in the head above #1.
In any event, one factor not touched on yet is the intake air. If the intake is getting air from inside the engine bay and not so much outside air, it will translate into hotter coolant when working the motor.
I will look into the edge, thank you. I understand factory gauges are not accurate, just going off what i have to work with. Since the turbo swap temps will intermittently spike hauling light loads, can only imagine what will happen once pulling a loaded trailer and bed full. I am running and s&b cold air intake, which is routed thru the factory "ram air" bumper inlets. The s&b had a silicone plug in the box, opening the box up to engine compartment temp air if the owner wishes. My plug is installed, only sucking thru the "ram air" .
With the '96 cross over, will i have issues converting to the balance flow water pump, as far as cavitation? I want to upgrade to the duramax fan, im sure that will help immensely, but want to avoid double buying clutches, adapting to the 4 bolt then screw on, or vise versa dependant on which water pump will work best.
With the '96 cross over, will i have issues converting to the balance flow water pump, as far as cavitation? I want to upgrade to the duramax fan, im sure that will help immensely, but want to avoid double buying clutches, adapting to the 4 bolt then screw on, or vise versa dependant on which water pump will work best.
Attachments
ak diesel driver
6.5 driver
With your set up you most likely have the low volume water pump. An upgrade would be to use the 97-98 water pump as it has more volume. A better upgrade would be to use the 99+ water pump as it's balanced flow so it flows more equally around the engine. I really like my electro viscous fan clutch as it's activated by water temp so no lag time waiting for the thermal unit to heat up. Plus I have an override switch so I can anticipate the big hill coming up.
Right on, I did look into electro viscous briefly. Read a couple post about it on here and elsewhere.Im wanting to do the 99+ pump, but have read conflicting info. Some claim its fine with single thermostat, others claim there is cavitation issues.
ak diesel driver
6.5 driver
There's even some that think the single version flows more hence why yours is sought after by some
Will L.
Well-Known Member
Many people say the flow is way better with the single stat, because we tried it! I think @WarWagon did it with his also, I am not sure who else here.
The argument of the dual is that more volume flows across the duals open than the single open. Could be. I just know I tried it both ways with my 93 and found the single stat with the spin on pump kept temps down more and recovered faster when it would hit 210 using the single stat than double stat. And i had mechanical gauge along with factory one in the dry & hot southwest. Maybe other places the dual did better?
If you run the dual stat, you need a restriction to 3/8” in the line that goes from the stat to the waterpump to force more water to radiator instead of pushing hot water back through the engine a second time.
If you wanna try the dual stat, and find it’s better for you- just speak up and there is a list of folks here that want your current one because of the a/c compressor location.
The argument of the dual is that more volume flows across the duals open than the single open. Could be. I just know I tried it both ways with my 93 and found the single stat with the spin on pump kept temps down more and recovered faster when it would hit 210 using the single stat than double stat. And i had mechanical gauge along with factory one in the dry & hot southwest. Maybe other places the dual did better?
If you run the dual stat, you need a restriction to 3/8” in the line that goes from the stat to the waterpump to force more water to radiator instead of pushing hot water back through the engine a second time.
If you wanna try the dual stat, and find it’s better for you- just speak up and there is a list of folks here that want your current one because of the a/c compressor location.
X2 or 3... how old is the dammed fan clutch? They only last 5 years max because they loose 200 RPM per year. 200*5 is down 1000 RPM! Old fan clutches and GM's garbage 6 blade fan have gone to the scrap yard more than once still bolted to the engines they caused the demise of. Even the lowly 6.5 power levels wrote a power check GM's ignorant engineers couldn't figure the cooling out for.
Ignorant from the rumor that fan noise complaints caused GM to raise the kick in temp on diesel fan clutches...
Cooling is more than the cooling system. It's also the exhaust system and related restrictions including turbo's that have too much back pressure.
The dual Tstat housing doesn't block the return path and mixes hot coolant with cool incoming coolant. Single T stat housings block the "warm up" path and force all the coolant through the radiator.
Before getting too exotic the best you can do is get a HO pump and low temp fan clutch. I ran the 4 bolt style just fine, but, better is the spin on style. Get that, freshen up the timing chain because you are more or less there, and get a Kennedy Diesel fan clutch. I have run both the 9 blade steel and Duramax fan. The Dmax fan pulls more air at idle for AC, but, flexes some at RPM. Pulling a grade flat out the steel fan does slightly better. Most outside the extreme temps I am in won't notice the diffrence. Give the system more "room" with a 185 T-Stat.
185? Yeah stomp the pedal to the floor at the start of the grade. Tstat is shut, fan clutch is "off". Engine starts to heat up and continues to so so till the fan is locked in. T-Stat opens. Radiator heats up. Fan clutch starts to see the hot air and starts to open the valve. Fan takes it's time to lock in and FINALLY after all these obsolete delays the fan finally gets with the program. Your ECT has shot sky high while waiting for the fan. 10 degrees "sooner" on the TStat simply drops the entire temp curve to stay away from the 210 mark. How you use the truck determines if you need this headroom: aka towing grades like I mentioned.
And stop at 210. Consider anything over 210 "RED" on the temp gauge. Because: Cracking of the block, heads, rings loosing temper... Rings be the first thing to get ruined with heat and here comes the instant blowby. 210 Is max temp you want to see, period.
Ignorant from the rumor that fan noise complaints caused GM to raise the kick in temp on diesel fan clutches...
Cooling is more than the cooling system. It's also the exhaust system and related restrictions including turbo's that have too much back pressure.
The dual Tstat housing doesn't block the return path and mixes hot coolant with cool incoming coolant. Single T stat housings block the "warm up" path and force all the coolant through the radiator.
Before getting too exotic the best you can do is get a HO pump and low temp fan clutch. I ran the 4 bolt style just fine, but, better is the spin on style. Get that, freshen up the timing chain because you are more or less there, and get a Kennedy Diesel fan clutch. I have run both the 9 blade steel and Duramax fan. The Dmax fan pulls more air at idle for AC, but, flexes some at RPM. Pulling a grade flat out the steel fan does slightly better. Most outside the extreme temps I am in won't notice the diffrence. Give the system more "room" with a 185 T-Stat.
185? Yeah stomp the pedal to the floor at the start of the grade. Tstat is shut, fan clutch is "off". Engine starts to heat up and continues to so so till the fan is locked in. T-Stat opens. Radiator heats up. Fan clutch starts to see the hot air and starts to open the valve. Fan takes it's time to lock in and FINALLY after all these obsolete delays the fan finally gets with the program. Your ECT has shot sky high while waiting for the fan. 10 degrees "sooner" on the TStat simply drops the entire temp curve to stay away from the 210 mark. How you use the truck determines if you need this headroom: aka towing grades like I mentioned.
And stop at 210. Consider anything over 210 "RED" on the temp gauge. Because: Cracking of the block, heads, rings loosing temper... Rings be the first thing to get ruined with heat and here comes the instant blowby. 210 Is max temp you want to see, period.
Husker6.5
135' diagonal 16:9HD, 25KW sound!
Heed @WarWagon 's words. This man has blown up and/or melted more 6.5's and components than anyone on here. Something about those 110°+ Arizona temps and long, steep grades pulling heavy trailers, I guess. LOL! He has tried and tested so many combinations to keep coolant temperatures below self-destruct mode.
@ak diesel driver Electroviscous clutch? Where do I find specs on that?