Inline thermostat mod
#21
I wonder how much is limited by the water pump design. Too bad there is not a high performance option. Mone is fine during the 90+ deg weather here in the midwest. But 100+ and a long grade who knows.
Has anyone heard of the theory that the piston drops below the water jacket on the downstroke creating a hot area that can't be efficiently cooled? I read it on a different forum somewhere is a rant. no idea if it is true or not.
Has anyone heard of the theory that the piston drops below the water jacket on the downstroke creating a hot area that can't be efficiently cooled? I read it on a different forum somewhere is a rant. no idea if it is true or not.
#22
#23
I'm not sure about the loosening of the cap method. I mean, if you have a head gasket problem, yeah, it makes sense. But, these trucks are designed to run at 20psi. The pressure helps lower the boiling point and it seems to cool more efficiently. I had the CARRS 4x4 aluminum reservoir on my Disco. It only has a 16psi cap and it would spew coolant from time to time. Once I put the plastic one back on, no spewing and my temps were more stable. That's just my experience. If I can find a 20psi cap for that reservoir I'll put it back on.
#24
I'm in Florida. My temps get up to 208-212 when driving 65+ on the highway. Here's my most recent experience.
Ambient: 90 and high humidity
Cruising around town 50mph, light to light, AC on high: 194-197
Stopped at a light for a minute or 2: 197- 202
Highway 65+ mph: 208-212
Ambient: 90 and high humidity
Cruising around town 50mph, light to light, AC on high: 194-197
Stopped at a light for a minute or 2: 197- 202
Highway 65+ mph: 208-212
#25
The high ambient temps and associated driving temps you have are pretty close to what I am seeing as well. I haven’t really had a chance to drive it much in nice cool wether to see how it acts then. Bakersfield is a hot unyielding hellscape in the summer. That being said it is where I live so I want to go wheeling occasionally when it is 100+ outside and still run my A/C. It is crazy to me that these motors wouldn’t be able to handle an incline in the heat at low speeds without me having a panic attack staring at my Ultra-Guage.
As someone mentioned low range will help keep the revs up. As you get up in elevation you will lose power obviously requiring more fuel input but also the ambients drop. You might want to consider dual electrics (I have them on my off road rig) as a way to keep the airflow up at low speeds, doesn't help with water pump speed but again low range).
Doesn't get very hot in England or Germany in the summer, they weren't really keen on the Desert testing way back when these were designed.
Sidebar - one of the guys I went to school with in the late 80's was from Sweden, summer job was at Volvo inc. After graduation he got a job at their Phoenix proving ground where they were doing high temperature testing of turbos, brakes, cooling systems etc.. This was late 80's, not sure if LR was their yet. I think they all do it now though.
#26
I wonder how much is limited by the water pump design. Too bad there is not a high performance option. Mone is fine during the 90+ deg weather here in the midwest. But 100+ and a long grade who knows.
Has anyone heard of the theory that the piston drops below the water jacket on the downstroke creating a hot area that can't be efficiently cooled? I read it on a different forum somewhere is a rant. no idea if it is true or not.
Has anyone heard of the theory that the piston drops below the water jacket on the downstroke creating a hot area that can't be efficiently cooled? I read it on a different forum somewhere is a rant. no idea if it is true or not.
#27
At least keeps me from getting speeding tickets.
Joking aside, I rarely go past 55 even when not pulling a trailer as my fuel mileage greatly decreases
#28
A little information from my run this weekend I ran 183 -186 low speed off road, 3rd gear under 40 KPH (24 mph) hitting 188 - 194 occasionally on uphill stretches depending on the length of the grade ambients were 28C / 82 F no heat or air
Hi way speeds 183 -194 (50 and 65 mph), higher on the uphills average was 186, except on long 8% + grades usually hit 196. 199 once but I was already at 188 from a long slow traffic line and running hard to pass said line of traffic, dropped to 171 on the downhill on the other side
On way the home I hit 3 very slow sets of traffic ambient 29C about 84F - no heat or air
Hi way speeds 183 -194 (50 and 65 mph), higher on the uphills average was 186, except on long 8% + grades usually hit 196. 199 once but I was already at 188 from a long slow traffic line and running hard to pass said line of traffic, dropped to 171 on the downhill on the other side
On way the home I hit 3 very slow sets of traffic ambient 29C about 84F - no heat or air
- 30 minutes at about 3 to 5 mph uphill etc in 2nd gear never broke 194
- Sitting for 30 minutes hit 199 put her in park rev's the throttle dropped to 190 in side of 2 minute
- 30 minutes of serious 0 to 3 miles an hour 194 to 197 same as number 2 dropped to park rev'd the engine to drop the temp
#29
What is the dual electric mod? Two A/C fans run in series? I’m not opposed to a Single electric fan to replace the vicious fan, but I don’t really want to mess around with finding and modifying a shroud that doesn’t wok as efficiently. I just ordered the 2991/Dorman fan upgrade, and a new reservoir cap. I think the fan will help with another degree or two the cap is just a precaution.
Last edited by Black Dynamite; 07-26-2021 at 02:48 PM.
#30
Not so much limited by water pump design as by pulley size, and even that limitation is only at idle. You can test that by shifting to third which speeds up the engine and water pump with minimal increased load. Have not heard the water jacket theory but can confirm it is incorrect in both details and theory. Piston skirt is the only part that comes below the jacket that section of the block is cooled quite well by both the motor oil and the conduction of heat through the aluminum block. Our biggest limitation is radiator size vs horsepower required to move 5000 lbs of brick up a grade at 70 mph. Its a BTU in vs BTU out problem.
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Richard Gallant (07-26-2021)