OVER HEATING

[Jinx Reyneke]

Hi Guys, I've been out of the loop for a bit. Very busy out here in the bush. Had a recent 2000km round trip. on the last 600km's started some strange overheating.

1)The radiator that is used for cabin heating sprung a leak through a long crack where the pipes and rubber hoses connect, on the top of the unit. I routed the hose in a loop excluding the heater radiator. Bought a new unit.

2)Still the temp kept climbing, changed thermostat.

3)Tried with no thermostat and blocked bypass pipe.

4)Flushed radiator and cleaned fins.

5)Put on new pressure bottle cap

6)Have tried all sorts of combination's of above.

7)Made the Viscous fan a fixed unit.

Nothing doing still overheats

The strange thing is that the pressure bottle fills with water and squirts out the bottle but the water is cool'ish But when you open the bleeder nut on the of thermostat housing just steam comes out. There is no water in the oil or oil in the water. So this build up of pressure makes me think itis a head crack or a gasket gone that allows gas to get into the water system.

The whole engine was overhauled about 70-000km ago. Question: If I replace the head, there are a few different thickness of head gasket depending on the clearance. If I go for the thickest will it make any difference? I ask this as I'm way out in the sticks and need to do this myself and need to get the parts brought in.

Would appreciate some comments.

Sorry forgot to say it is a 96 TDI300

[uganda110]

Jinx, I'm just north of you in Uganda with a 94 300TDI. I recently had a similar issue.

Is it possible that you've got an airlock? These 300TDI are famous for them around here. Here's how I solved my problem (won't cost you a centavo, but your pride will be shot).

1. Unscrew the plugs on radiator and thermostat housing (if you haven't already changed these to brass ones, do it! Those plastic bits are so easy crack).

2. Fill the radiator full and cap it off.

3. Fill the thermostat housing full, but don't cap.

4. Have someone open the cap on the overflow tank, put their mouth on the hole and blow, creating pressure (this is the bit where your pride will be hurt)

5. Someone else can use the palm of his left hand and cover the thermostat housing hole, while simultaneously squeezing the lower hose coming from the radiator (all the while, someone should be blowing in to the overflow tank).

6. You should hear air bubbles gurgling around when you squeeze. After squeezing, remove your hand from the housing and allow the bubbles to escape.

7. Repeat 4-6 until all the air is out.

Before you do any of this, get rid of that loop and repair the heater connection. Those loops are usually the cause of this problem.