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Heath Cooling Upgrade....Update

Big T

Big T

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After much delay due to inability to time my engine as a result of operator error, I was finally able to do some extending test driving. Engine runs great and it's a bit louder on cold start up at -1.94 TDCO, but I have to really listen for that. Again, these are SoCal temps at 45 F in the morning. Truck runs great.

As for the cooling mods, on hard driving at varying speeds up and down hills, the coolant temp tends to shoot right to 210 before the fan kicks in and quickly knocks it back to 190. Same thing when coming to a stop at the top of a hill: approaches 210 and quickly drops back down. At cruising speed on the highway, temp stays between the first and second notch past 185, or about where the AC Delco T-stats open. During variable speed driving, the temp will move around between the steady state to a tick or two above 200. I have two bottles of watter wetter in the system and the rad and all coolers were cleaned spotless.

Hard to say what this will do during hot ambient temps. Definitely different than when running the Robert Shaw 180 t-stats where the temp simply stayed pegged just below 185, unless I was pulling a big grade and or towing up a grade. After speaking with Todd at Heath, he suggested keeping my 180 t-stats in case I did not like the result. I honestly believe the 5 to 7.5 degree difference in base temp does little for engine performance or mileage. I liked the cooler operating temp as it gave me peace of mind. So jury is still out and I really need to test this towing a boat or trailer up to our place at Big Bear Lake in the local mountains and do so during the summer.

Honestly, just happy to have the truck back and running at this point.:thumbsup:
 
Those temps do not sound normal to me. When I had my 98 it would take some serious effort to make the temp gauge budge past the 185 mark. The temp should not shoot to 210 on an unloaded 6.5, something sounds wrong...
 
That's why I posted it. It never shot to 210 on the prior cooling system ('97 HO pump with dual cross over t-stat housing and stock '95 fan & clutch).
 
MINE :

Everything standard -> cooling system, radiator, waterpump

EXCEPT the single T-stat and the FanClutch mod !


With the OEM 195°F T-Stat the temp gauge went over the 210°F mark while pulling 5 tons. With the Kennedy 180°F T-stat the needle stays at 185°F and goes only about hair over the 185°F.

Why spend so much money in a cooling upgrade, when you can have the same result for about 30 bucks (T-stat plus shipping to germany) and the clutch mod for free ?


Cu,
Sven
 
I must agree, that although many make the claims that the 180 stat doesnt help, I know it does, and so many others do too. It wont solve a broken system, but it does aid a system operating correctly, but not already good enough.

With 180 stats I have a hard time even getting over 180. After some 100+ mph runs down the highway and then slowing down to stop it will get almost to 190. I have stock low flow pump and single stat, with SSDS clutch and DMax fan. Obviously my fan clutch never needs to kick in. Only time it did was a traffic jam on Vegas Hwy, running AC, operating 6 hours straight. At that time my gauge still only read about 190, but scanner on PCM was almost 210.

So dont always trust the gauge.

I would say you shouldnt see that hot when running empty, I lived in LA, now central coast. Did you use antifreeze as well, or just water and water wetter? Did you flush out the radiator and block at all? The old orange crap left a lot of sludge in my radiator that I got out.
 
50/50 coolant and distilled water. Don't know anything about orange crap as I've never used it. Technically did not flush it, but had the rad out twice and had to refill each time.

Air in the system? How do you get that out? Is there a bleeder on the system? Is that the screw on top of the t-stat housing? If so, when do you bleed it?

Yeah, those can make claims about their low temps using stock pumps, fans, 180 t-stats, but they never did it for me on this engine. Even the dual 180s with HO pump would see 225 going up to Big Bear Lake during August, not towing.
 
I've cleaned the radiator (outside) the way Heath recommended: soaked in scrubbing bubbles and pressure washed mucho times.
 
well, so you have a 50/50 coolant mix, plus two bottles of water wetter. With water wetter you should not use a 50/50 mix. Unless you think you are going to be in sub zero temps.

Anti-freeze makes the system less efficient. I would maybe do 20% antifreeze plus one bottle of water wetter then the rest distilled water. I only have about 10% antifreeze in mine. Unless you are in sub-zero temps, which in SoCal you arent going to find.
 
I hooked up the GMTDScan and went for a 16 mile run around town, returning parts and stuff I did not use. It went to a tick below 210 on the gauge and the GMTDScan was at 180. Once it was fully warmed up, it stayed below 194.7 for 95% of the time, with other 4% being 195.7 and 1% at 197.5 each time briefly at stop lights or after shutting down and sitting while going into stores. Meanwhile, the gauge showed much more variability, going up to two ticks below 210 and a tick above 185. I had one time where it was at 197.5 on the GMTDScan at start-up from being parked at a store and the guage was at 185.

Based on the GMTDScan, I believe that I'm within the operating range of the AC Delco T-stats.

Have always used 50/50 mix as I was led to believe that ratio also was best to prevent boil overs. I can see water being a better conductor of heat, but not better at preventing boilovers. Not when water boils at 212 and this engine regularly would hit that towing up a grade during sunnmer. Just sayin.

Got to hop and set some crawdad traps. It's that time of year to be fishing for the big largemouth bass.
 
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Sounds like its working OK then, just a little warmer than before in normal operation. Hopefully it is stable under load. The gauge does measure from the drivers side head and the PCM from the passenger side thermostat housing, so variability is in location and sensors and gauges.

The purpose of water wetter is to prevent corrosion and boiling, so you dont have to use less efficient anti-freeze. It doesnt take 50% to prevent boiling, just to prevent freezing.
 
Why would the gauge and PCM measure from two different locations? Does that mean there's two different sensors working on this coolant issue? You guys are so technical.
 
It is what it is, two sensors. And getting the flow and temp balanced is something Heath's kit attempts to do, but the sensor itself and the wiring to the PCM or gauge or the grounds conditions and everything is variable.
 
Did some 4 wheeling today with the wife and dogs. Wifey was doing her geocaching thing and we were on Cleghorn Road off I 15 in the Cajon pass. Lot of offroaders out there and it was a good test for the slow grind up the steeps, which is typically when I'd see high temps. It never got above 195 on the dash guage. GMTDScan stayed at home. We climbed as high as 5,000'. Often behind trains of jeeps and early style Broncos (I have a '73). Truck really purrs and I like the clatter at -1.94. No leaks either.
 
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