Hi all, first post. I know i should be posting something in the new members forum but im a busy man so im gonna get straight to my questions. My Dads Land Rover has some issues, ill stick to the cooling problem on this post to keep things organised.

It's a 95 with the 300 TDI. it overheated on me once bigtime. smoke comin out and stuff. I was using it for like 2 hours before it decided to spazz out. the radiator was empty somehow, when I went to fill it, I'd put water in the reservior and it would fill up the reservior, and then it would very slowly start going down, and id have to fill it up again and repeat about 7 or 8 times. it took about 30 minutes to fill the thing.

oil does not appear milky, in fact, its the cleanest oil ive ever seen come out of a diesel........

it was fine after that for a while, temp reader was allways at about half way ( i read thats normal for this car)

the other day it started to get on the hot side, about 3 milimeters form the tom white line

when i touch the radiator its cold, the top 2 hoses have no pressure, and are cold, and water is slowly coming out of the filler cap, which is also cold.

Im pretty sure I have a blocked somehing somewhere, probably coming out of the reservior. it seems the water pump is pressurising the reservior and the flow to the radiator is blocked, hence why the water exiting the filler cap is cold.

I dont really know allot about cooling systems and how they circulate. I was wondering if someone could tell me how this sysem recirculates and where the most likely point would be blocked, or if they think its something else like the thermostat.

 

1. Attached are pages from the RAVE shop manual for the 300 cooling. You can also download the whole manual for free if you like.

2. Like any closed water system, it needs to be full, and no big air pockets inside. If you have loss of coolant, could be a loose hose, gasket, etc. Look for leak. Should not have to keep refilling coolant. You can also rent/borrow a coolant pressure tester and pump up air pressure (about 18 PSI in the cooling system, and watch for leaks over 30 minutes or so.

3. The system has a visocus drive fan. While that won't leak coolant, it can make engine overheat at idle or slow. The fan clutch is viscous, has silicone fluid inside. When engine is cold, spin fan by hand and release. Should go maybe a 1/4 turn, feel like peanut butter inside. Repeat same test with engine fully warmed up. This time it may go a little further, but should no freewheel.

4. There is an in-the-block thermostat, usually about a $10 item. Swap out if any doubt.

The coolant pump has an in/out hose set, they would be cooler than the center hose from engine (#5 in attached drawing).

5. Radiator can be partially clogged with mud in fins, or clogged internally. If you have the brass/copper radiator it can usually be chemically flushed, the tank unsoldered and calcium buildup rodded out for under $100 US. If any work has been done on system important taht fan blades are back on the cooreect way and belt route is correct. Holding a plastic bag near grille should not be blown away from truck, should suck toward grille.

 

Thanks for the informative reply. very happy with the manual.

im not having to refill the radiator frequently, this happened the first time i overheated.

the other day, the same thing started to happen, and there was fluid coming out of the reservior cap, i figured that was how the fluid leaked out that day because I cant find any leaks. after leaving the car sitting a few days, no fluid has leaked out.

I just visited my mechanic and he sais the thermostat, and im starting to think so to, because the other day it worked fine, he sais it might open some times and other times no, i just dont understand if thats the case why fluid is coming out of the reservior like its overpressurised.... wouldnt it just recirculate like its running cold?

 

If overheating, water becomes steam and forces its way to the reserve container, can also make some hoses rock hard, etc. Thermostat is the cheap part of the system. Radiator when warmed up should be about same temp top to bottom, much cooler bottom indicates sludge blockage.

 

Nicholas Rowland Ellis is a bussssssy man!

 

If the upper radiator hose is cool to the touch as well as the bottom hose then your water pump is bad.

 

thats what I thought but the water coming out of the cap is actually cold!!!! it should be boiling hot its really weird..... the whole radiator stays cold to the touch and the top hose is totally limp no pressure at all.....

i thought the water pump but i can see water moving around in the reservior when i start the car, which is cold.

the only possibility i see is that the water pump is overpressurising the reservior causing cold water to burst out of the cap. would a bad thermostat cause this type of blockage?

 

A stuck closed thermostat will let very little water pass, the water pump pressure would be forced through the heater pipe bypass circuit, which may account for the pressure into the reserve container. Suggest remove thermostat and at least inspect, will need a gasket to put it back on. If no stat available, you can pop that one into a pot on the stove and heat it up to see if it opens. You can also loosen the top hose on the water pump and see if any water is passed out when truck is running. Thermostat is more likely than water pump. The pages I sent you have a path chart for the water flow.

 

I live in costa rica, my mechanic sais i dont actually need it here because its so hot, he sais that just take it out and ready, but is it really that simple? do i need some sort of bypass or osmething to stop it going to the cylinder heads?

 

No, they can just take it out. As warm as it is there you can live without it for a while to be sure that was the problem. I would suggest you have a thermostat, but it is OK to remove it for diagnosis. It may work best with a good thermostat.