Still overheating, what next?

Ok, here's the history, perhaps you all can help me diagnose...

1. The car had overheated before I got it, and it was in non running condition. No compression on one bank of cylinders. Other side not tested. Oil was way too full and when I took the drain plug out, loads of coolant was in there with the oil. Suspect bad head gasket.
2. I took the engine apart. One piston had a small part missing off the side.
3. I took the block in to get it machined. Liners appeared to be in correct position. Heads were skimmed, deck was skimmed, oval cylinders were rebored, fitted oversize pistons, line bored, oversize crank journals.
4. Took the radiator to be tested. It was blocked, with really bad flow. Great, I found the problem which caused all this mess, I thought. Bought a refurbished radiator.
5. Got everything back together, new upper and lower rad hose, used
expansion tank.
6. Used viscous fan and clutch, although the clutch may not be working properly. I don't think this is the problem because it overheated at 70mph one time.
7. Randomly overheats. Sometimes can drive for ages with no problem, sometimes it overheats over and over.
8. New water pump. New thermostat. Play with timing although I'm not sure where it needs to be.
9. Notice the vacuum advance does not work on the distributor. I can suck air through the pipe.


Current symptoms: Usually overheats 2 miles from leaving my house with a cold engine. Sometimes the needle will climb close to the red and then go back down, and it'll be fine after that. Sometimes it will insist on overheating and I have to stop the car.

No white smoke, No water in my oil. Perhaps I have an air pocket in the cooling system, but I have tried to bleed that several times including driving the car up on something to try and get the reservoir higher than the top rad hose.

Any ideas what else I should try? Not sure if I have a bad block or bad heads, or if I just have a really stubborn air pocket that I just can't get out. It doesn't feel like there's any water in the top rad hose, and when I disconnected it from the thermostat housing to replace the thermostat, no water poured out. But I can't seem fill it up. There's no bleed screw on the D1.

Thanks,
Roger

I dont know much about V8's but my 300tdi turned out to be a blocked heater matrix, if thats blocked then it stops the flow of water through the engine.
Bitch of a job to do.

symun said:

I dont know much about V8's but my 300tdi turned out to be a blocked heater matrix, if thats blocked then it stops the flow of water through the engine.
Bitch of a job to do.

Click to expand...

Could be I suppose... If I take the hoses loose and hook up a hose pipe to one and see if the flow looks good, would that be a good test?

Well I took both pipes loose to the heater matrix. I took the top one off first, and no coolant came out. I took the bottom one off and a little coolant dribbled out. I hooked up the hosepipe and it flushed through the radiator OK, Good rate of flow. So it's not blocked.

The car did overheat yesterday, and the reservoir was full at the time, but it's empty this morning. So I guess the cooling system needs bleeding again. I wish I could find a write up on how to bleed the air out of the cooling system on a d1. All the write ups seem to be for a d2 with a bleed screw on the top rad hose. I'm not sure if I'm doing it right.

Thanks,
Roger

Hi Roger,

To bleed the system, you can get the vast majority of the air out by running up to temp with the reservoir cap off and then, at fast idle topping up and replace the cap. The engine should purge itself from then on so you might need to top up again a couple of days later.

But your problem doesn't sound like a bit of air in the system to me!

I offer two suggestions for possible culprits.

I know you replaced the thermostat but new part quality is not what it used to be. As a test I would remove the thermostat, cut out the sprung loaded mechanism and replace the resultant 'disc with a hole on it' and see if this improves things. You should always have coolant in the top hose as it is below the level of the reservoir.

The other suggestion is a bit more off the wall as I can't remember if it is possible to do this ......but......is there any chance you could have fitted the valley gasket back to front? If it is possible and you did, this would block the waterways to the inlet manifold.

That's the best I can come up with....hope it helps. Full marks for sticking at it BTW, it can't be easy over there in jeep country!

Cheers

Chris

Thanks for the ideas. I tried two different thermostats, both new, both from two different land rover parts suppliers, and I tested the first one in a pan of water on the stove when I took it out, and it opened correctly.

I looked at the valley gasket when installing it and I couldn't tell a difference when it was 180 degrees it looked the same. Can anyone confirm if it's possible to get these backwards? If it is possible then there's a 50:50 chance I got it wrong.

Thanks,
Roger

beebe said:

I looked at the valley gasket when installing it and I couldn't tell a difference when it was 180 degrees it looked the same. Can anyone confirm if it's possible to get these backwards? If it is possible then there's a 50:50 chance I got it wrong.

Roger

Click to expand...

Hi Roger,

Forget what I said:doh:

I just checked a spare gasket and it is symetrical. In my defence, I've built a lot of different engines over the years but I haven't done a RV8 for a while. False Memory Syndrome!

Sorry

Chris

Hey, no problem. I appreciate any ideas. I just went over to Nigel's car place over here in Arkansas about 20 miles away. He took out the carpet on the passenger (right) side of the car and it was soaking wet. Leaking heater core, by the looks of it, although it wasn't blocked. I figured I'd loop a hose from the two pipes coming from the engine, to bypass the heater core after I got home, But I got a mile from Nigel's place and it overheated. One of the pipes going TO the heater core had sprung a leak. I went back to his place and took a hose from one of his old landys and made the loop and drove all the way home. Give me a few days and I'll post here and let you know if it solved it.

Thanks,
Roger

Try taking the viscous fan off, mine would overheat with it fitted. Don't know why but when I got up to temp it would carry on and get hot, I found out it was that after running around all winter with no fan fitted then fitted it and it got hot. A lot of people don't even fit them during summer, but I've fitted a electric one just incase. Worth a try anyhow regards Steve

I'll try that, thanks,

Another thing, I noticed - if it overheats, it normally does it 2 miles after starting from cold. And then if I get out and take off the coolant cap, all the water gets sucked out of the reservoir, and I have to top it up. Then I can drive for ever with no problems.

Cheers,
Roger

if it's yoiking all the water in like that, it seems like its an air pocket or lack of cooling problem, rather than the fact that there's water there but it cannot cool the engine, if you get me.

try taking the thermo out all together, maybe that will help/allow the cooling system to prime up fully when it starts - chances are its overheating before the thermostat opens, and the thermostat being closed might be causing the lack of water you're having in your block.

i dunno, it might help, or change something for the better or worse - but its another idea.

weird that once you allow water into the engine it's happy - but then the water doesnt stay there!

i would be warming it up, remove your tank cap and get the water suck thing, then fill up to level again. then allow to cool and see what happens.

all that water cannot be disappearing!

hope that helps

I think I got it fixed... time will tell. I bypassed the heater core, which was leaking into the front passenger carpet so I couldn't see it.

I drove it after that and it overheated once. I think this was an airlock because it sucked in water again when I took the cap off of the expansion tank. Then I filled it up, and I've driven it two times from cold since, without overheating.

The last two times, I got to the two mile mark where it normally overheats, and I see the gauge climb from half heat to about three quarters for about 30 seconds to a minute, and then go back down to half again, then it stays there. Maybe it's working out the last of the air. At least it's not going into the red now.

Did my first oil change since the rebuild today. The old oil didn't look too bad.

Thanks for everyone's help.
Roger