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Discussion Starter #1
Finishing the last few details of the Suburban that has become my DD.

Not quite overheating but some cooling issues.

Truck sits at 180 degrees all day, if I leave it idling it on a hot day it will hover between 180-200 and AC performance suffers. The use of the high idle switch helps cool it off after a few minutes.

On the highway if I push it I can get the temp up to 190-95 if I am hot rodding (80-90 plus)
Yesterday I towed a 4-5k boat and watched EGTs. In the am (75 degrees) Would go up to 1200 accelerating up onto the highway but cooled off to 800-1000 while cruising 60-70mph. Coolant temps were between 190-200.

On the way home temps were closer to 95-100 and egts were the same, never over 1200 and never higher than 950 sustained. Coolant temps got to 200-205 and stayed there. I heard the fan clutch engage a few times and it cooled off back to 190 or so. When I pulled into the house and left the truck idling for a few minutes’ temps spiked to 215-220. I hit the high idle and it went back down to 200 in a minute or two.

With all of the available cooling upgrades done I assumed I would not encounter ANY cooling issues moving forward.

The only thing I can think of is, like the LLYs the restrictive intake is causing the issue. I have not touched the intake system at all except replacing filter.

Any thoughts? Intake is basically all that I have left to do. Truck has 4" Exhaust, crossover pipe, PMD relocate, OPS relocate, NEW OPS, carter lift pump, Champion 4 row radiator, 99+ water pump, 180 degree tstat, Duramax fan and hayden fan clutch, brand new stock injectors and glow plugs. Quadstar single tune with gauges (pre turbo EGT). Vac pump deleted, has turbomaster set to max out around 9-10 lbs of boost. 3.42 gears and 285s.

One note, truck does exhibit low-ish oil pressure (verified with manual gauge in line with OPS). Hot idle is 10-12 lbs. Hot 2400RPM is about 28-32 psi. I run Rotella 15-40 T4 and a quart of Lucas synthetic which has helped add 2-5 lbs of pressure across the board. I was worried but it seems to run fine.

2. Year of truck/engine. - 1995
3. Odometer reading (indicate miles or kilometers). - 153,000 miles
4. Indicate the model number on the Injection pump (starts DS4 or DB2......). Stock
5. Indicate if you know if it’s a 1500, 2500, 2500HD, 3500, 3500HD. - K1500 Suburban
6. Do you have an EGR on the engine? (An F or an S engine code 8th VIN digit) - No
7. Air Filter condition (visual check). – New Stock box and filter
8. Fuel filter condition (freshly changed, mileage since changed). New
9. Location of PMD/FSD? (ex. on pump/remote over intake, behind bumper). - New Leroy Kit behind grill. New wire.
10. Outside Temperature (C or F). _ ° - 100F
11. Service Engine Light while running?- on/off/intermittent
Intermittent. When I idle it or set it on high idle it comes on. If I start driving or blip the throttle it goes away. Is not on when I start the truck.

11a. Service Engine light does glow during start/cranking/bulb check: Yes/No – yes
12.Have you scanned for engine codes? Yes/No - no
13. Condition of Battery terminals (removed, cleaned and tightened). - new
14. Known condition and age of Batteries. - new
14a. Are batteries a matched set of same age? - yes
15. Condition of Major Grounds (removed, cleaned and tightened)
15a Have the batteries been individually load tested? - All new and replaced 3 months ago.
16. Does engine crank, or "turn over"? - Yes
16a. Does engine start and run? - Yes
18. Does your Wait To Start light come on? - yes
18a.Number of seconds WTS light is lit. - 10
19. Engine Cranking speed (if you have an accurate tachometer). - fast
20. Are you experiencing Stalling? – no
20a. Describe the event (upon startup only, down the road, hit a bump, etc...) - see above.
20b. Do you notice loss of dash or instruments? - No
21. Check turbo inlet and air filter for obstructions. - Clear
24. Upon cold start, does the radiator hose get hard quickly? Yes/No - No
25. Upon cold start, do you have excessive white smoke? Yes/No - No
26. Do you have excessive cranking time before the engine starts? Yes/No - No
28. Are all glow plugs in proper working order? - Yes new
29. During hard acceleration, do you have excessive black smoke? Yes/No - No
30. Do you have any unusual exhaust smoke issues? - No
31. Turbo check out - Pass/Fail - Pass
32. Indicate fuel that you are using: Bio-Diesel, #2 Diesel, SVO/WVO, other - #2
33. Are you using any fuel additives? If so, please list. – atf occasionally
34. Upon unscrewing fuel cap, do you have a large vacuum formed in the tank? Yes/No - no
35. Do you have any service history available that might pertain to the problem you are having? – probably poorly maintained lol.
36. Please indicate any modifications to the vehicle that might help us diagnose better.
 

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Tstat needs to be the OEM 190*or 195* AC/Delco. 180* is not the proper one.
Installing a k47 air intake from a 97'+ year Chevy Diesel will help
 

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Discussion Starter #3
I read 180 is best for extra hot climates. I also left out I have dexcool and a bottle of diesel Redline water wetter in there.

I ordered AFE intake so we shall see how things go. Any further input in greatly appreciated.
 

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I read 180 is best for extra hot climates. I also left out I have dexcool and a bottle of diesel Redline water wetter in there.

I ordered AFE intake so we shall see how things go. Any further input in greatly appreciated.
If you are close to the border towns and constantly drive in LA type traffic of stop and go or heavy tow then the 180* will work, otherwise stick to the OEM stat
 

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A intake, any intake isn't going to help with cooling at all...
A clean cooling stack, better flowing W/P, & fan clutch would help, and like dually said, 180* stats would maybe help but is only a band aid..
 

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Discussion Starter #6
A intake, any intake isn't going to help with cooling at all...
A clean cooling stack, better flowing W/P, & fan clutch would help, and like dually said, 180* stats would maybe help but is only a band aid..
Every other single mod has been done already, the intake is all that's left to change. Stack including condenser is brand new.

from my post:

Truck has 4" Exhaust, crossover pipe, Champion 4 row radiator, 99+ water pump, 180 degree tstat, Duramax fan and hayden fan clutch and brand new stock injectors and glow plugs. Quadstar single tune with gauges (pre turbo EGT). Vac pump deleted, has turbomaster set to max out around 9-10 lbs of boost.
 

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What you are describing is the effect of 180F t-stat.
If that is not what you want, then get ACDelco 190F.
There are also 2 types of ACDelco, make sure you get the OE not Professional.

And the intake will not impact coolant temperature.
Intake impacts the Exhaust Gas Temperature (EGT).
 

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Discussion Starter #8
What you are describing is the effect of 180F t-stat.
If that is not what you want, then get ACDelco 190F.
There are also 2 types of ACDelco, make sure you get the OE not Professional.
I have read that it’s the best bet in the extreme climates.... Its 100+ 6 months or more a year here. I don’t understand why it opening sooner would make heat soak worse.

I followed Max cooling and haven’t gotten the same results. I just removed the fender snorkel and opened up the box a little to see if it helps before the intake gets here Monday. LLYs had heatsoak issues from a restrictive turbo inlet so maybe this is the same.
 

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My cooling got better when I went to New intake I also got the Marine snorkel instead of that garbage flat smashed flat intake manifold. If your already getting the upgraded inlet filter go buy a intake hat with the large inlet
 

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Removed the snorkel and fender tube for now. Bumped boost from max of 9 to 12 on turbomaster. EGTs are down and it seems to be better except the cruising boost went from 4-6 to 6-8psi.

Will report back when I hook up a trailer after intake gets here.
 

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Removed the snorkel and fender tube for now. Bumped boost from max of 9 to 12 on turbomaster. EGTs are down and it seems to be better except the cruising boost went from 4-6 to 6-8psi.

Will report back when I hook up a trailer after intake gets here.
When you hit 12psi+, the ECM will put the engine into limp mode just FYI.
 

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Discussion Starter #12
When you hit 12psi+, the ECM will put the engine into limp mode just FYI.
As per my original post, Quadstar single tune to address that issue. I had not adjusted boost after I installed chip.
 

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Discussion Starter #13
Ran much cooler with the same load yesterday, never hit 200 much less 210. All I have done is remove the fender snorkel, the intake should be here this week and I am sure will improve it further.

I guess the fender snorkel is restrictive enough to contribute to overheating.
 

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Discussion Starter #14
Update, installed AFE cold air intake. Worst AFE product I have ever encountered, did not fit without trimming to fit the coolant hose and bending metal. I had to redrill mounting holes to make it bolt up And make an extended PCV hose to reach the supplied connection.

I have probably installed 50 cold air intakes in my life and this one took the cake. I should have read reviews before I tried to save the $40 over the S&B. Complete garbage, I will replace when I can with S&B,

Will update on if it rectified the original issue.
 

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I can tell you that the afe intake is going to make temps worse. I had one on my truck and later switched back to the original with some mods it lowered my intake temps by at least 50°F also after going back to stock my egts will never go over 1100°F and my coolant will never go over 210°F.
 

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I can tell you that the afe intake is going to make temps worse. I had one on my truck and later switched back to the original with some mods it lowered my intake temps by at least 50°F also after going back to stock my egts will never go over 1100°F and my coolant will never go over 210°F.
Great lol.... I'll post my results in the interim.

Ill just drive it for a few weeks until I can just order the S&B intake.
 

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Discussion Starter #17
Towed the same load yesterday and noticed an improvement over the stock 95 intake. Temps never got over 190 and EGTs in OD at 60-65 were 1000-1050. Very manageable considering the load and the tune the truck has EGTs easily go high if you put your foot in it.
 

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Great lol.... I'll post my results in the interim.

Ill just drive it for a few weeks until I can just order the S&B intake.
There are three of the later model OEM K47 round hi-cap intake setups on eBay last I checked, ranging from abt $150-250, iirc.

Personally, I prefer the look of the OEM can to the SBC unit. Not sure if there are any performance advantages to one or the other, but I’d bet the ACD rplcmt filters prob cost a lot less.
 

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300$ for AFE intake? It's litterally just 3 walls of plastic and a curved tube with a K&N filter copypaste.
The only viable intake for these trucks are the K47 diesel intake. NOT GAS VERSION.

And if you are still struggling with heating issues, I will reccommend water injection.
 
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