Cooling A 1.6

[DeadEye]

Engine is a 1.6 12mm with mechanical head. Its in a boat so I am in question about proper plumbing. The temp gauge says the engine is over 200 but suspect it not that hot. Anyway I went to change the thermostat and found an empty housing. Is the thermostat on the side of the head or the back end of it? Both locations seem to have a thermostat housing with a sensor on it.

Should the radiator ( heat exchanger in my case ) be hooked to side of head near end of IP or the end of head? Presently the exchanger is hooked to side of head and the large fitting on coolant pump.

The coolant fitting on end of head is hosed back into the pump (I would think this was ment for the heater core). Is this plumbed right? Sorry for such foolish sounding questions

[CarlosA]

The thermostat itself is in the water pump housing. I can`t really help with the rest - a jet boat I had once had the water go around the headers to warm it up before going into the engine, else the water would always be too cold.

[DeadEye]

Thanks Carlos. This gives me a start point for working on it in the morning. This thing acts like a stuck stat to me. The input and output raw water temp (not the engine antifreeze) is luke warm,this tell me its not removing heat from hot engine. Ill pull the stat tomorrow am. Lots of things it could be though. Mud inside exchanger, the pump, ect

[82vdub]

The coolant to the radiator (in a car) comes from the flange on the front of the head (injector side), while the return from the radiator goest to the water pump. The flange on the end of the head feeds the heater core, and there's the return pipe from the heater core that goes back to the water pump. Plus, there's the bypass hose that goes from the front of the head to the water pump. That's how it's run in a car. Thermostat blocks the water coming back from the radiator as it's in the bottom of the water pump

Is your application open cooling system or a closed type? If it's open, these diesels may not really warm the water much, as the water flowing through the engine may pass fast enough where the heat output of the diesels is low enough where it just barely gets warm. Also note that 200 degrees is only 5 degrees warmer then a (possible) thermostat temp rating. I wouldn't worry about 5 degrees.

[vwtyp133]

A few years ago after a cooling system flush on a 1.5na, thought I'd just run about 10-20 miles with plain water & without a thermostat in place, having previously done that on many other non-Vdubs, just to get better neutralizing/flushing of any cleaner possibly trapped the system, as well as to see how cool it would stay. Surprise! Got about 2 miles from home & the temp gauge went HOT & the system boiled over! Duh... well, I've been told that, at least for the IDI VW diesel vehicles, the thermostat -open or closed- has to be in place to get proper circulation within the block & head; of course the head is where the majority of the heat is.

Naturally, once the stat was back in place, there was no problem (Lucked out again!). Live & learn. No experience with VW diesels in boats, but it seems like the circulation pathways would be similar. If so that would sure explain high head temp coolant readings. Good luck there.

[DeadEye]

The coolant to the radiator (in a car) comes from the flange on the front of the head (injector side), while the return from the radiator goest to the water pump. The flange on the end of the head feeds the heater core, and there's the return pipe from the heater core that goes back to the water pump. Plus, there's the bypass hose that goes from the front of the head to the water pump. That's how it's run in a car. Thermostat blocks the water coming back from the radiator as it's in the bottom of the water pump

Is your application open cooling system or a closed type? If it's open, these diesels may not really warm the water much, as the water flowing through the engine may pass fast enough where the heat output of the diesels is low enough where it just barely gets warm. Also note that 200 degrees is only 5 degrees warmer then a (possible) thermostat temp rating. I wouldn't worry about 5 degrees.

Its a closed system. The antifreeze is circulated by the pump through engine and exchanger just the same as in a car with a radiator only difference is we use water passing through instead of air passing through to remove the heat. It has a fill cap for the antifreeze same as in a car and 4 ports , two for antifreeze and two for seawater also incorporated is the exhaust manifold that is also cooled. The water after doing its job cooling engine is injected inside the exhaust pipe thus cooling the exhaust pipe from the inside and acting as the muffler yep it quiets the exhaust very well.


Thanks on the hose run down ( I am properly hosed )

[TylerDurden]

Without a t-stat, the bypass hose will recirculate hot water directly into the pump and overheat the engine... the tstat has a block-off plate that closes the radiator-bypass when engine is at temperature, sending all flow to the radiator.

Water Pump ports:

• COLD: Bypass open, radiator closed
  HOT: Bypass closed, radiator open

[DeadEye]

Without a t-stat, the bypass hose will recirculate hot water directly into the pump and overheat the engine... the tstat has a block-off plate that closes the radiator-bypass when engine is at temperature, sending all flow to the radiator.

Water Pump ports:

• COLD: Bypass open, radiator closed
  HOT: Bypass closed, radiator open

Thanks again Tyler. I removed the t stat to to some more testing this morning and was quite pleased with results. T stat removed the engine never exceeded 130 at extended idle confirming the exchanger is working. The flow through exchanger was low due to the bypass being open still it flowed enough to cool (albeit engine not under load). I am waiting for the auto parts to deliver the new 160 stat (special order)

On to a few more questions. The temp sensor being read is on the port( injector side of engine) there are two more sensors not hooked up one is on the port for heater core and another on the head right beside it what should they read when hooked up?

Thanks again D.E.

[air-cooled or diesel]

1st temp sensor should be on front of head about the middle, 2nd is on rear of head, flange going to heater core. 3rd sensor on rear of head sounds like oil pressure to head.

[82vdub]

Since this is a marine application, not all sensors would be used like they would be in a VW chassis.

The sensor on the end of the head is an oil pressure sensor. VW's use a dynamic oil pressure sensing system where it uses both a normally open and a normally closed switches located at the head and on the oil filter flange. One operates at low RPM, and one at higher RPM. When little gremlins show up in this dynamic control system, simply unplugging a sensor to eliminate the oil warning buzzer does not solve the problem, it makes it worse.

The sensors on the flange on the head going to the heater core (VW chassis) are for the glow plugs and dash temp gauge (there's two used in the VW chassis).

The sensors on the flange coming from the front of the head are for the AC cutoff switch.

I'd say that your marinized system may not be the same as the VW chassis system, and if it's not wired now, it may not need to be wired.

[DeadEye]

Since this is a marine application, not all sensors would be used like they would be in a VW chassis.

The sensor on the end of the head is an oil pressure sensor. VW's use a dynamic oil pressure sensing system where it uses both a normally open and a normally closed switches located at the head and on the oil filter flange. One operates at low RPM, and one at higher RPM. When little gremlins show up in this dynamic control system, simply unplugging a sensor to eliminate the oil warning buzzer does not solve the problem, it makes it worse.

The sensors on the flange on the head going to the heater core (VW chassis) are for the glow plugs and dash temp gauge (there's two used in the VW chassis).

The sensors on the flange coming from the front of the head are for the AC cutoff switch.

I'd say that your marinized system may not be the same as the VW chassis system, and if it's not wired now, it may not need to be wired.

Thanks a Million 82 that answered the questions pretty good I THINK.

So I should pull one of them and replace it with a sensor to read pressure. This explains why the oil pressure gauge is not working ( I thought it was the gauge itself )

BTW the stat is now in and all cools and heats as it should.

Thanks All.

[Fatmobile]

What does your oil pressure sender look like?
Just a small; 1 inch switch?
VDO gauge that isn't working?