Overheating question

[FalcoColumbarius]

I'm putting my chip on the "air in the system" scenario. The stock thermostat for a Starwagon is 82°.

Perhaps (when the engine is cold) remove the rad cap and run the engine with the hand throttle set to 1,100rpm (or so), go fetch a beer from the fridge, come back and watch for bubbles with a coolant mixture handy (and a funnel) in case the coolant level goes down. Also check that the overflow bottle is filled to the correct level. If there is air in the system what typically happens is an air bubble gets trapped at the thermostat. This air bubble then works as a buffer between the coolant and the thermostat's paraffin wax valve thingy. When this happens the wax valve thingy doesn't feel the heat that's building in the water/coolant so it doesn't expand, which is what opens the thermostat. If the valve in the thermostat doesn't open ~ the coolant doesn't flow, ergo doesn't get cooled and the engine overheats.

Heat is power, which is why there's a thermostat in the first place. You want the engine to get hot so it delivers power to the propeller shaft/axle to make the wheels on the bus go round and round. When the engine gets too hot the thermostat opens and the coolant does it's job ~ keeping the engine from getting too hot, yet hot enough to deliver the power. Delica(te) balance, just like your bowels... smiles.

Falco.

P.S.: What kind & brand of coolant are you using?

[FredVenne]

Hey guys, just 8 days before leaving and we are experiencing the same thing. The overflow canister is well overflowing. So my first thing to look at is the thermostat. Now here is my question, for those that keep following this post, how about removing entirely the thermostat and put a new one in winter. We don't need heat this time of the year. What are your thoughts?

Cheers!

[gezzza]

You could drill a small hole or 2 in your thermostat to aid flow. Plus i used nulon water wetter and straight rain water in my cooling system for a year and temps were always 3 or 4 degrees lower than using coolant.

[FredVenne]

So basically, nobody has ever tried driving without a thermostat?

[robinimpey]

I wouldn't think that's a good idea as the engines are designed to run at a certain and constant temperature. That's just my $0.02.

[thelazygreenfox]

Fredvenne
I tried no therm on my L300. The engine ran cooler, but was difficult to seal at the thermostat connection w/o the therm in place. I was also unsure as to where the water flowed with the therm removed.

It's crritical to divert the cooling water to the bypass line that flows around the engine to #3 (?) cylinder. In an L300 the therm opens and diverts water flow to the bypass but with the therm removed sufficient water flow may not be diverted. I know... it initially feed your heater cores but ends up cooling at the head. Plugged heater cores are also part of the problem as they normally remove much engine heat in the summer. Try bypassing the heater line and watch your engine temp rise.

The bypass is a stainless tubing that flows out of the therm. towards the rear of the engine ending at the #3 cylinder head.

I still believe Manitoba Deli is correct with his belief that too much fuel (pedal) causes the 300 and 400 engines to crack heads. The (dated) premix chamber introduces a cool air/fuel mix to a hot head and presto cracked heads. Butch (CVI) showed this on an L300, 400 and a(mazda?) head at his latest "Appreciation Day."

As long as you tread lightly you should never crack your head.

good luck
TLGF

[Rattlenbang]

I'm wondering if he got the same kind of new rad as I did, because I get the same issue: work the engine hard and the rad cap can't keep the system pressurized because of a poor casting where the rad cap is supposed to seal. I doubt mine is the only one if it's from the same supplier. I got mine from Maxoverdrive and I'm going to have to contact them and ask about warranty. You'll only see this if you push it doing hill climbs, normal driving about town doesn't raise the temperature and pressure enough.

[sinbad]

The clutch mechanism on the cooling fan starts slipping with age and can reduce the airflow through the radiator. Bugs etc in the radiator or between the radiator and the aircon condenser can also reduce cooling capacity. It's not a loose fan belt by any chance?

[FredVenne]

Alright then, I will change the thermostat. Have been reading some post and it seems to be as complicated than removing the turbo. Now my 1000$ question; it seems to be some confusion about the part number for the thermostat. Some got a bigger one (that seem to be working fine). Have been looking and cannot get the proper #. Anyone can tell me with assurance what is the proper part#?

Thanks a million!!!

Fred

[sinbad]

Thermostat
I got told by an engine re-builder not to run these engines without a thermostat, the pump needs the back pressure it seems. However he did say you could safely remove the opening part of the thermostat but not the whole thing.

[FredVenne]

So again, about the part #.

I have read a thread that suggested the part# in Wiki was not the proper one.

Is it any of these 2?

And what is the differences between?

Stant 13398 180°f/82° c<--standard temperature
Stant superstat 45398 180°f <--standard temperature

Fred

[glenn]

Fred, last summer, 1/2 way down to Yellowstone I started noticing that I was losing coolant through my overflow bottle. I foolishly made the decision to keep going, even though I suspected the head was cracked. I loosened the radiator cap, and drove very, very conservatively. This allowed the pressure from combustion to exit the cooling system without building up pressure and draining out the reservoir. Sometimes it felt like we could walk faster than we were driving - but it let us finish our vacation and got us home. There were no other symptoms - no burbling, no white smoke, coolant looked normal. Once I got home, sure enough it was a cracked head.
I'm not advising you to go on a vacation with cooling system issues, but if you find yourself in the same situation as me, it might get you home.

[FredVenne]

I am really sorry for bringing this up again, but I need to know what is the part# I should look for and where I can get it. Anyone out there can help?
I'm trying to reach CCAuto but no answer. I need this part ASAP, this is why I am pushy...

Fred

[lrp374]

I have a 13398 which was given to me by Noel of Enviroimports as the correct thermostat some time ago. He has worked on lots of Delica's so I presume it would work. It has 54mm stamped on it which i presume is the diameter.

Hope that helps.

[FredVenne]

So right in the process of switching thermostat and some coolant dripped over the alternator... bad or not to worry about?

Fred