Massive oil/coolant mix after replacing thermostat

Hello there.

I cannot think straight on this one any more. Any advice appreciated.

Model: 1998 Freelander 2.0 XEdi (Not the TD4)

The thermostat started playing up on our Freelander, so we bought a new thermostat.

Fitted new thermostat to old housing under oil cooler. Used old O-Ring as I didn't have a spare.

Themostat housing starts leaking water massively. Tightened up the screws just in case. Tightened top one up so tight the flipping bit snapped in the screw (I'll admit it was a pretty shoddy bit I was using & not paying enough attention). Could not longer remove housing...

Tried gunging round the housing without success. Only option Pa-in-Law recommended was to smash off the old thermostat housing & get a new one. Do the job properly.

Got new housing & O-Ring.

Refitted - still leaking badly.

Now I had fitted the O-Ring inside the thermostat housing, as it appeared to be small enough to fit.

Thought occurred that I could have sworn the old O-ring was on the outside, around the tube of metal the protrudes from the oil cooler itself.

I took off thermostat housing, put O-Ring around the tube (fitted nicely - better, I thought).

I noticed that this tube has holes running through it & a couple had been bashed when I smashed off the old housing.

Put thermostat housing back on hoping for the best, thinking that if the resulting leak was only a drip, then I could use some RTV sealant the next day.

Wife said she needed the car for a trip tomorrow, so thought to myself: Fill up with water & leave overnight to see how bad the dripping leak is. She might get a short trip to town & back.

Filled up with water, ran engine to bleed system. Left it running for a couple of minutes after the system had bled as I wanted to see the water circulating.

After a minute of two, loads of coolant started pouring from the water reservoir, followed by LOADS of oil. I mean it was haemorrhaging out of the water reservoir.:doh::doh::doh:

I'm at the end of my tether now.

Have I put the O-Ring on completely wrong? I assumed it went around the protruding tube of the oil cooler as that's where the old one was, I'm sure.

Has knocking some of those holes in that tube screwed up the oil cooler completely or have I just put the O-Ring on stupidly.

Any advice on how to resolve this?

I'm thinking:

1) Drain water system & flush many times to get oil out of water system.
2) Check oil for water on dipstick (pray there is none) oil change if there's water in the sump.
3) Remove thermostat housing again
4) Tuck O-Ring on the inside of the thermostat housing
5) Apply generous amount of RTV silicone on the metal plate round the protruding tube where the housing meets the oil cooler
6) Screw everything back in place, let silicone harden & add water
7) Pray...

Please correct me if any of these steps are wrong. Either way, the wife's going nowhere tomorrow!

I'm posting 2 images of the oil cooler minus thermostat housing.





I've ringed 3 areas that I damaged removing the housing.

Would this damage be the reason why the oil is mixing with the water? Have I permanently damaged the oil cooler?

Is there any chance I can repair this or would putting the housing back together properly be enough?

Any advice appreciated here.

burn it baby..

Trust me, that crossed my mind when I saw the oil coming out the expansion tank!

I'm trying to even work out how oil got into the system from this point in the first place.

What I don't want to do is put all this back together, change oil & silicone it and then have all my brand new oil dumped through the system again.

What if I simply joined the oil pipes & bypassed the oil cooler whilst I get the leak fixed? Would that be very harmful to the engine?

looks knackered to me m8, get yourself a new one m8 or at least a good second hand unit, that will never seal again.

Possibly the worst news I could have had. Appreciated, though.
Saves me trying to refit the housing & wasting another 6 litres of oil!

Looking online a new one costs a few hundred. I'll keep looking.

I did see a 2nd hand oil cooler from eBay from a Rover 45TD. Bizarrely it looks exactly like the one for my Diesel Freelander. It is a Rover engine after all:

ROVER 45 TD OIL COOLER AND THERMOSTAT on eBay (end time 03-Jul-10 12:11:56 BST)

Am I going mad, or would this do the job? This is more within my price range & cools oil, let's be honest!

Look at it this way. You asked if removing the cooler will damage the engine. The answer is simply that Landrover / Rover put an oil cooler there to keep the oil working. If you remove it and the oil overheats it will become too light and stop doing its job. Result, blown engine. Now if oil is getting in to the cooling system at the rate you suggest then there is clearly a failure, the result is a loss of oil pressure to the engines load bearing surfaces, leading to the same result, a blown engine.

Only proper solution, replace the oil cooler entirely, and take care with your torques next time.

Good luck,

Dave

matthewbyrom said:

Possibly the worst news I could have had. Appreciated, though.
Saves me trying to refit the housing & wasting another 6 litres of oil!

Looking online a new one costs a few hundred. I'll keep looking.

I did see a 2nd hand oil cooler from eBay from a Rover 45TD. Bizarrely it looks exactly like the one for my Diesel Freelander. It is a Rover engine after all:

ROVER 45 TD OIL COOLER AND THERMOSTAT on eBay (end time 03-Jul-10 12:11:56 BST)

Am I going mad, or would this do the job? This is more within my price range & cools oil, let's be honest!

Click to expand...

get all the dimensions off yours and phone him and see if he will measure it up for you over the phone, yours has to come off now anyway so it's worth a punt.

You're right of course, Dave. That damage needs to be replaced & the oil cooled as the engineers intended. The wife said try sealing off the holes on the damaged side, but I doubt there's any hope of that. I'll have to get a second-hand unit as my local dealer quoted me over £450! :faint2:

That eBay seller is away until 15th June. I'll give him a call to make sure of the size, but connections-wise it looks identical. As you said, Gegs, the cooler's got to come off anyway, so I might as well remove the unit & compare with the picture.

Thanks for all the advice. I'll let you know how I get on.

Finally sorted, thank God!

Rover 45 oil cooler was totally wrong size, judging by the dimensions the gent on the phone gave me. Much longer than a Freelander diesel engine. Shame as I thought that might have been a handy source of engine parts in future.

Finally found a 2nd hand oil cooler from a firm in the Midlands for £80. Was delivered & I just fitted it. Drained sump for complete oil change (I hope to avoid getting gunge in the filler cap, but there was a fair amount of water in there. I think I'll just have to keep cleaning it out for the next couple of months.).

Filled cooling system with water. Needed to drain out some oil from the bleed screw as some was still left up there.

Ran engine & diverted the water return line into a bucket to avoid gunge going into expansion tank. I reckon I'll also be needing the clean out the expansion tank regularly for the next few weeks too.

Took the ol' girl for a 20 minute run after a few start-run-stops to clear the cooling system as best I could. All systems normal.

Thanks again for all the help. Flippin' relief to get her running again!

top job matthew, sounds like you got out well for £80 !