[outofdoors]

Background before the question...

- Cooling fluids changed out 20k km ago
- Last couple of (short) trips engine temperatures sky-rocketed (just below top of gauge)...damn hot actually.
- Gauge is twitchy around 3/4 range...(irrelevant?)

Flushed out the coolant this weekend and hosed down/out internals as best I could and replaced with new green stuff. Visually good green coolant fluid came out during the flush but there was some (not a lot) of brown sludge.

(also changed out the thermostat to the 71 deg C unit but the old one (81 deg C?) was definitely working.

The result of this effort was quite spectacular. Engine temps is now less than half range on the gauge. Very good but it leaves me with some concerns.

Questions to the more experienced (352 NA...):
- Is the coolant system THAT sensitive to a bit of dirt?
- The pump does not seem to deliver much flow/pressure...any non-shop/factory testing suggestions?

Michiel

 

[Chas Stricker]

It sound like the T-stat could have been intermittent. I've had them like that and then they just stick...opened or closed. Had this not cured the problem I would have also looked at the pump shaft, in case the shaft was spinning inside the impeller. Do most of you folks use the colder T-stat?
Chas

 

[DokaTD]

I would be looking at your temp gauge. When not if they fail they will read super high with only a 10* change. Meaning your new lower temp t stat could just be keeping you under the threshold that sends the temp gauge through the roof. I have both a high precision and the factory gauge on my truck. At 175*f both gauges agree, but at 180-185*f my factory gauge climbs very high showing severe overheat.

 

[erwin Z]

20k on the clock = how much time ?
Antifreeze, when it loses its life and it does, one side effect is cavitation. This will play havoc in itself. It also fails to lubricate the pump.

Also, the seals don't last without fresh coolant. Pure water kills seals quick.

Curiosity has me asking, why put a cold thermostat in it ?

 

[DokaTD]

Curiosity has me asking, why put a cold thermostat in it ?

Lives in Australia and I'm guessing it's a bit warm since he is having cooling issues. Just a guess

 

[erwin Z]

That's exactly why I asked.

The thermostat would spend much of its time open. Not stopping in the rad long enough to get cooled by the fan, the incoming coolant would already be hot, much like running without a stat at all possibly.

Looking through past threads, what rad cap are most running for pressure ?

 

[DokaTD]

That's exactly why I asked.

The thermostat would spend much of its time open. Not stopping in the rad long enough to get cooled by the fan, the incoming coolant would already be hot, much like running without a stat at all possibly.

Looking through past threads, what rad cap are most running for pressure ?

Are you being serious?

 

[erwin Z]

Well, im not being funny.

Try running an engine without a thermostat in a hot climate. A slow moving heavy machine like a Mog, and give it some elevation under load, it will over heat. The rad wont do much for the cooling process.

 

[Mogasaurus]

My popcorn is in the microwave. . .

 

[erwin Z]

Don't over heat it

 

[DokaTD]

Well, im not being funny.

Try running an engine without a thermostat in a hot climate. A slow moving heavy machine like a Mog, and give it some elevation under load, it will over heat. The rad wont do much for the cooling process.

Oooohhh sweet Jebus!! Help me Oprah Winfrey!! Save me Tom Cruise!!!

 

[erwin Z]

If I remember correctly, Oprah wasn't big in Texas. Don't know about Tom Cruise.

 

[Britbike2001]

Sorry bub but you need to spend a tiny bit of time with fluid dynamics, or perhaps some common sense.

Toss the thermostat in the woods and you have full flow through the radiator. The engine will not be happy because it CANNOT reach proper operating temperature BEEEEEEEEEEEECAUUUUUUSEEEEEEEEEEeeee all the fluid is passing through the radiator and losing energy and not maintaining the design temp. The design temp allows all the tolerances to be keep in their proper ranges. Air cooled engines have wicked lapse tolerances due to the wide range of operating temperatures, since there is no controlling thing like a thermostat and coolant. They are less efficient because of this.

I think I learned this when I was 10.

Catch up.

 

[erwin Z]

Well Bub, air cooled and water cooled engines are not alike.

Before you toss the thermostat into the woods,

1. The thermostat is the weakest link in the system. It is supposed to be.
2. The thermostat controls how cool an engine runs, not how hot.

I learned this when I was 14.

Fluid dynamics ? Im sure that is why water pumps are rated in KW's and not gpm ?
I could be wrong with this one, and I have been known to be wrong.

Also, mixtures of water and antifreeze also changes those dynamics if I remember correctly as well. Example, 50/50. 60/40 etc. The higher the content of antifreeze, the less efficient. 100 % water flows the best, but offers no lubricity or protection to the seals.

Which also brought me to the Q, what pressure cap is being used. That brings the boiling temp up dramatically. A hotter engine is more efficient than a cold running engine.

That's as common sense as I can get.

 

[DokaTD]

Sorry bub but you need to spend a tiny bit of time with fluid dynamics, or perhaps some common sense.

Toss the thermostat in the woods and you have full flow through the radiator. The engine will not be happy because it CANNOT reach proper operating temperature BEEEEEEEEEEEECAUUUUUUSEEEEEEEEEEeeee all the fluid is passing through the radiator and losing energy and not maintaining the design temp. The design temp allows all the tolerances to be keep in their proper ranges. Air cooled engines have wicked lapse tolerances due to the wide range of operating temperatures, since there is no controlling thing like a thermostat and coolant. They are less efficient because of this.

I think I learned this when I was 10.

Catch up.

Ouch

 

[outofdoors]

Well, well...

Chas, yes I do believe the thermostat was intermittent.

DokaTD, After reading your (1st) reply I spend some time searching for previous conversations. This one one started by yourself caught my eye. Did you drill a hole for the second sensor or did you use a surface (glue on) type?

 

[DokaTD]

Well, well...

Chas, yes I do believe the thermostat was intermittent.

DokaTD, After reading your (1st) reply I spend some time searching for previous conversations. This one one started by yourself caught my eye. Did you drill a hole for the second sensor or did you use a surface (glue on) type?

I used a second blank plug and drilled it for 1/8npt. My new sensors sits just next to the factory sensor. Eventually I will remove the factory part all together because I don't believe in the integrity of the factory parts and would never trust them.

 

[DokaTD]

Well Bub, air cooled and water cooled engines are not alike.

Before you toss the thermostat into the woods,

1. The thermostat is the weakest link in the system. It is supposed to be.
2. The thermostat controls how cool an engine runs, not how hot.

I learned this when I was 14.

Fluid dynamics ? Im sure that is why water pumps are rated in KW's and not gpm ?
I could be wrong with this one, and I have been known to be wrong.

Also, mixtures of water and antifreeze also changes those dynamics if I remember correctly as well. Example, 50/50. 60/40 etc. The higher the content of antifreeze, the less efficient. 100 % water flows the best, but offers no lubricity or protection to the seals.

Which also brought me to the Q, what pressure cap is being used. That brings the boiling temp up dramatically. A hotter engine is more efficient than a cold running engine.

That's as common sense as I can get.

Erwin just single handedly solved everyone's over heating issues for ever!!!! Everyone go out and buy a bunch of Tstats to keep your engines cool!!!!

 

[erwin Z]

Thanks, but I cannot take credit for that with the stat installed.
The system was already created.

On a personal note, I prefer a 190F stat.
50/50 mix in summer, 60/40 in winter.
For the cost of it, its cheap to do a test of your own. Draw your own conclusion.

Smoke may decrease.
Fuel economy might improve.
If you cold winter drive, you will enjoy a warm cab.

 

[Tmax]

Erwin just single handedly solved everyone's over heating issues for ever!!!! Everyone go out and buy a bunch of Tstats to keep your engines cool!!!!

i think they key to Erwin's success and probably his strogest asset is his ignorance.