1996 Disco 1 overheats

[gourmetchic66]

Help Help need some ideas on why my rover is over heating? New heads. All new gaskets. Etc............. The only thing I can think of is aftermarket thermostat or needs new radiator cap? Also checked waterpump. Runs really good for me and then the hose gets hard...as a rock! ( no smart ass answers) **** Does anyone know? would love to get her running soon!!!!

 

[joey]

First how many miles?

Second have the radiator chemically tested (to ensure you are not getting pressure for a bad head issue)

Third have the radiator flow tested to make sure it isn't clogged.

Fourth an most important do not drive it if it overheats as it will **** the Engine in short order.

 

[greg409]

As Joey alluded to, the chemical test should detect combustion gases in the coolant (common cause of rock hard hoses)

This would indicate a poor head job (seriously, no pun intended)

You state - new heads, drive it thru' their front window.(that was a pun)

Ditto on the do not drive.

luck,greg

 

[antichrist]

I'll assume you didn't install the thermostat backwards.
While unlikely, don't overlook the possibility of the new thermostat being defective. It's a good idea to test them before installing.
Have you checked the viscous clutch for the fan to make sure it's working properly? It's about the easiest thing you can check.
If you've never had it worked on, the radiator is a very likely suspect for being clogged in a vehicle that old.

Did you do the head or someone else? If someone else, they shouldn't have given it back to you with an overheating problem.

 

[Chongo]

1996 Disco 1 overheats

Help Help need some ideas on why my rover is over heating? New heads. All new gaskets. Etc............. The only thing I can think of is aftermarket thermostat or needs new radiator cap? Also checked waterpump. Runs really good for me and then the hose gets hard...as a rock! ( no smart ass answers) **** Does anyone know? would love to get her running soon!!!!
__________________
Deborah


Hi Deborah, From a cold engine to rock hard radiator hoses, How long does this take with brake on @ 1500rpm in gear? Immediately? …….. 1-3 minutes? ……… 5 or more minutes? This will tell us if there is a breech in the sealed coolant system, it could be as simple as a radiator cap, if it is immediately then it’s most likely a combustion chamber breech.

Does the exhaust smell funny?

Are you loosing radiator fluid / coolant? And how long ago?

Is the check engine light on ? and for how long?

Last radiator flush?

Last coolant and coolant system service?


215 Buick v-8 Engine

The engine in the disco 2 is the old buick 215 v-8, with no roller cam, and no rotators on the exhaust valves like US engines. The dry cylinder sleeves, “ these are not wet sleeved engines”, are straight, un - flanged and made of steel, while your block is made of aluminum. This creates a thermal condition of dissimilar materials. Many mechanics blame a blown head gasket on this thermal condition as a, “dropped liner”, but in reality at about 210 degrees operating temperature the cylinder liner actually moves around .004” of an inch away from the head gasket ring , this releases the tension on the head gasket between the liner and the head. This also releases the tension between the head and the head gasket between the liner and the head, and reduces the heat sink value on the head gasket steel ring, {this is why when you remove the old head gaskets on a land rover the steel ring on the head gasket is usually yellowish or has a burnished color}, causing premature head gasket failure. Now note what I said, the head to liner distance is getting larger by .004” not the head separating from the block, but the liner actually grows 50% shorter than the aluminum block walls. And since the stock land rover liners seat at the bottom of the bore, and on the main bearing saddles the expansion ratio starts at where it seats, at the bottom of the bore, not the top.
Expansion ratio of steel is 6 parts per million per degree
Expansion ratio of aluminum is 12 parts per million per degree.
No real such thing as a dropped liner according to popular belief, it is a thermal problem with dissimilar materials. And there is only one bullet proof cure, Top flanged liners, sometimes called top hat liners in the British market.
There just isn’t any other long term substitute for this issue. Different head gaskets are only a myth, not the cure, production short cuts caused this problem, Buick when they had built these engines cast the liners in place, Rover bored them out and pressed them in with polished side walls. Perfect ingredients for cylinder bore walking........Which is what happens.

Cracked blocks

A rare issue

Land Rover Bosch engine blocks, or the old buick 215 block usually cracks on the main bear saddle bulkheads, just below the liner. This is caused by the straight walled liner. Since the straight walled liner has no lip or flange at the top of the bore to seat against, it must seat against the bottom of the bore. Where the crankshafts main bearing saddle bulkheads hold all the tension from the tightening of the cylinder head bolts. As you tighten the head bolts, the head is pushed towards the block, pushing the steal ring head gasket towards the cylinder liner, forcing the liner to push hard against the bottom of the bore in the block, which is the main bearing saddle bulkhead. Switching to top flanged liners eliminates this issue. This is a rare issue, but I have seen this
several in my lifetime with this engine.

Head Bolts

Head bolts must be replaced every time you remove the head, they are not regular bolts, but a special designed stretch bolt. There is a tightening sequence principle that must be followed although contrary to popular belief, and the service manual, as long as the principle is adhered to the sequence can be changed. The principle is uniformly and incrementally tightening the head down. The actual order doesn’t matter.
Take a good look
how the head gasket is designed and it comes with a sticky adhesive on the
composite part of the gasket. This will work beautiful if both surfaces are left
perfectly dry, and free of oil, i.e. lacquer thinner. Use NO OIL PERIOD on the head bolts, You’ll regret it if you do. You see the oil you put on the threads, like the book tells us to, will push off the threads as you thread it into the threads of the block and it
gets between the block and head pushing into the gasket areas ruining the effects of
the adhesive on the gasket, Oil and adheasive isn't usually a good combination......

What I did and this works well, I put only 2 layers of Teflon Tape on the threads of the new head bolts and a small amount of grease just under The bolt head. What this does is not let the bolt head gall into the heads and lubes The threads into the block without any oil. I believe this is an area where a lot of people have got themselves into trouble, and they followed the book. This would probably cause gasket failure in a few thousand Miles or so, and would probably be blamed on the mechanic or machinist, when it is A procedure problem. Use the Teflon tape on the bolts, it runs in nicely and life Is good.

In testing the book vs. torque standards I found the service manual, “again” in error as it says to tighten all bolts to 15 ft. lbs. then 90 degrees more in sequence, then a additional 90 degrees for final torque. This is bogus, and utter nonsense. My findings after doing this left the 3 long head bolts at 50 - 58 foot pounds of torque, while the short head bolts read 68 - 72 foot pounds of torque. I found that almost an additional 90 degrees was required on the long bolts for a total of 245 - 270 degrees before the long bolts achieved the 68 - 72 foot pound equivalent to the short bolts. This makes the tension and torque on all bolts even. If the tension on all bolts is not the same, I couldn't care less what you think, or what the manual says, un even head bolt pressure is one of the best ways to blow a head gasket.
Due to the dissimilar materials of the steel bolts and aluminum heads it needs a stretch bolt design. Don’t go buying studs for this engine, you won’t be happy with the long term effects.

Best wishes……..Chongo

 

[gourmetchic66]

Thanks for all of the replies

As of now, I have a thermostat and radiator cap ordered. We had aftermarket and maybe thats the problem. It takes 3-5 min to start overheating . We used new head bolts when we replaced heads. We are going to check radiator if these new parts don't work. Will let you know! Really appreciate all of the info. Got a really super sweet deal on this Land Rover and hoping this gets fixed soon!!!

 

[antichrist]

Every engine I've ever rebuilt has a specific tightening sequence for the heads, manifolds too. The reason being with a large flat surface is that you want to start in the center and work out. For the same reason when you have warped boards you start nailing in the center and work towards the ends.

If you're changing the friction on the head bolt threads, which you are by using teflon tape rather than oil, you can't really complain about the manual's torque being wrong, you've changed values that torque is based on.

Deborah, no, the aftermarket thermostat isn't the issue, at lease not simply by the virtue of it being aftermarket. I've been driving and working on Land Rovers for over 35 years and have never bought an OEM thermostat. Be sure to test the new one before you install it to make sure it opens and closes like it should.