Hi all,

Can anyone help me with an overheating disco 1, want to do a pressure test, what do i need to perform the task myself. My normal mechanic has done a runner with two of my vehicles, i am the proprietor of Camel feet | Adventure holidays - 4x4, Kitesurfing, Mountain biking Spain, Morocco an adventure holiday company which uses 4x4 vehicles for some of our tours.

Thanks,

Pete.

 

Wow, what a cool web site with pictures of Rovers getting paid to play.

Here is one form of pressure tester. Amazon.com: Mityvac MV4560 Radiator/Cooling System and Pressure Test Kit: Automotive Many parts stores cary a similar unit. Pump up to 18 PSI and watch for leaks.

You should also have independent radiator shops, which work on big trucks, buses, construction equipment - they can also do that, plus "boil" out the radiator with hot acid and unsolder a side tank then "rod out" calcium deposits.

Common overheats causes in a D1: low coolant, radiator sludged up inside, bad thermostat, radiator and AC condenser plugged with leaves and mud front or back, belt on wrong, fan blades on wrong, fan clutch worn out, AC condenser fan not working, bad head gasket, cracked head, cracked engine block, loose hose clamp. If exhaust gas in coolant from head gasket, usually makes sound of bubbles rushing under dash through heater core. In warm areas where heater is bypassed, this "self diagnostic" is not present.

Please post you future questions and comments in the D1 forum area, where they will get quicker response and more people looking at your issues (and web site).

 

sweet website. wish I could go

 

SavBuzz,

wouldnt it emit a vapor from the exhaust and a sweet smell ? I had a Taurus , and praying not a current LR , that blew a HG and it exhibited these traits. Rover purrs like a kitten. A hot kitten, but a kitten none the less.

 

An overheating Disco is not always a head gasket - but could be. Can overheat from low coolant, bad fan clutch, clogged radiator fins outside, clogged radiator tubes inside, bad water pump, serpantine belt threaded wrong, fan blades on backwards, electric fans dead, electric fans wired backwards, bad thermostat, stuck thermostat, no thermostat, and reported today - a bad tensioner combined with a serpantine belt contaminated with degreaser that dissolved a little plastic and hardened the belt - no squeal, but slipping while turning things at a lower speed.

The HG can leak outside (down the block, sometimes missed, sometimes burned off by hot exhaust pipes), inside into oil (milkshake time), inside into cylinders (can make white smoke out exhaust and that smell, but newer antifreeze is formulated to taste bitter to prevent intake by pets - so may not smell as sweet as in the past), and you can just have a plain old hose or clamp leak that eats coolant, sometimes only when driving, but you think it is HG. Sometimes the external leak is the valley pan or front cover or water pump.

And we almost forgot the heater core and plumbing to it.

So lots og things that can remove coolant fromt he system and make overheat if left unfixed. Can be HG, can be other things, can even be cracked block or head. But there are more cheap things that can make it overheat, or run warm. And the older the Disco, the more likely it will have more than one cooling system problem.

Many owners don't flush cooling system and radiator and replace coolant every 3 years. And they don't flush brake system. Or change tranny and transfer case and differential and swivel fluids. If you just wait until it all leaks all of it out that could be bad.

 

I checked my 96 Disco 4.0 thoroughly and still overheats...belt, belt routing, electric fans, fan clutch, exhaust gas in
coolant (negative), no coolant in oil and vice versa, no blockage to air flow thru radiator/condensor, new thermostat and water pump...after needle gets past 9:00, if I rev engine to around 2k, almost immediately goes to 9:00. I do hear rushing water in dash occasionally. Could I have not bleeded correctly? Seems very high pressure on hoses as well. Oh, I also had the cooling system power flushed...also new expansion
tank cap...PLEASE HELP!! Just got and wife ticked over cost
now!

 

In my limited experience, overheating problems that happen sometimes and seem to go up/down on their own are due to a stuck thermostat (which you mentioned you replaced) or air in the system. The bubbles under the dash supports this .....

In my case, I am getting the bubbles and air in the system from exhaust gas but you mentioned you tested this and it was not the case. Did you do a good bleed of the coolant system? Leave the heater on "1", full heat, defrost mode and run the truck at idle with rad cap and overflow cap off. Leave rad cap off until coolant with no bubbles begins to overflow (gets very messy while waiting) and then cap it. Keep topping off overflow tank as necessary if the level falls below the middle of the tank. Do this for about 30 mins while keeping an eye on the guage (although in my experience the bubbling coolant overflowing will tell you if its overheating before the guage will). Jacking up the truck's passenger front wheel also helps get the bubbles out.

Also, Are you loosing coolant? A leak could do this ... Perhaps pressure test the system? If nothing is letting air into the system and your thermostat is good I would guess the bleed is all that is wrong?

 

Just had a very similar experience with my 95 - I was lucky and figured it out before I spent more than the cost of some coolant. Bubbles under the dash can mean the coolant is boiling or just left over air in the system.

I flushed my system and refilled this morning and I simply filled with water until the expansion tank was full and left the cap off (as stated above) and let it run until the thermostat opened at which point the water point dropped. I kept my water jug right over the tank and filled exactly the amount that was pulled in to the system - keeping the level constant.

Drove all over Phoenix today (106 degrees) and not a single problem. Any other symptoms?

BTW - I had trouble fitting a pressure tester on the system, as the system I had didn't have the correct adapter :-/

 

Well if it is not the cap on the expansion tank and you have excessive pressure, I would lean toward combustion gases but you said that was negative.

I would be pulling that rad out and getting it checked out at an old fashion radiator shop.

The wife will have lots more to get mad about. You may have a difficult situation to face there!

 

Thank you...will try to re-bleed. And no. No leaks anywhere.