Total V6 strip down and rebuild - Wisdom greatfully received

arblickspule · 27th March 2019, 23:28

Hullo friends,

Soooooo, had an Head Gasket Failure on me baby. We backyard (well, front yard if your wanna get technical) "fixed" her and she failed a second time.

Not sure how well me Microsoft Sway will work on the forum but here's the link anyway.

https://sway.office.com/sZOBfSom7VOMLUDH?ref=Link

That was the first "rebuild" with little photography and only the rudest of commentary. She failed again (Poo in the oil now, not just the entire cooling system) and it seems we will have to take the engine to pieces once more. Only this time, much, much more.

I'd like to collect some advice and guidance from anyone who has gotten deep in the engine and either rebuilt or refurbished or even swapped out the KV6. Literally any advice.

It's me intention to photograph the entire process from taking off the acoustic cover to cleaning out the gunk from the oil sump. Haynes++ for people who are doing in their garden.

Thanks in advance and I hope me and my Pa can offer something in return.

Quote:

Reasonable people would have started flicking through AutoTrader. We, however, are not reasonable people. >8)

SD1too · 28th March 2019, 07:31

Quote:

Originally Posted by arblickspule

Soooooo, had an Head Gasket Failure on me baby. We ... "fixed" her and she failed a second time.

Sooooo Oliver, have you worked out why?

Simon

arblickspule · 28th March 2019, 08:27

Guessing at the moment, as she only broke down yesterday, that we, in all likelihood, botched the gasket job.

Initially, when she conked out it were due to, literally, the whole cooling system being clogged with emulsified oil. It was thick and everywhere. Every pipe, every cavity in the engine block, everywhere! None in the oil though. So we stripped out manifolds and removed the heads, cleaned as best we could, and popped her back together with a new gasket, water pump, thermostat, radiator, etc.

Now, bare in mind that we were actually only trying to see if it was worth salvaging. We never actually expected her to start again!

She did, and ran, with a slightly rich Bank 1, for a month before glooping up again. This time there be mayo in the oil too. Its entirely possible that we misdiagnosed the original issue but would have had to break her apart to clean anyway.

So, we're thinking we warped a head? Didn't really check to be honest as we weren't expecting any success. Anyhow, it's got to be done again, this time, without snow but with much more time on our hands. And much more experience.

350zwelgje · 28th March 2019, 09:35

Am thinking oil cooler issue originqlly as only oil in coolant, first time and this time (not head gaskets

)
Had this oil cooler issue on a diesel and diesels are more known for it, but can happen to KV6 as well.

It is an oil coolant heat exchanger in aluminium that can start to leak internally. Temporary by-pass is possible and you can see if the problem is cured. Perhaps it is not necessary to have a second go at the head gaskets.

Will do my KV6 distribution belts in couple of months and will change this cooler for a new one just to be sure....

Rob

arblickspule · 28th March 2019, 11:09

Interesting. Never considered that. It would be fab if it is that, nice and easy to get to! Will check that first before hoiking them heads off again!

Think we had to break her apart last time anyway as the mayo was just everywhere. I can't even estimate how much we removed. Gallons? It was just awful.

Got to get her home from Fleet before we can see.

Thanks for the input!

SD1too · 28th March 2019, 12:21

Quote:

Originally Posted by 350zwelgje

Am thinking oil cooler issue originqlly as only oil in coolant, first time and this time (not head gaskets

) ...
It is an oil coolant heat exchanger in aluminium that can start to leak internally. Temporary by-pass is possible and you can see if the problem is cured. Perhaps it is not necessary to have a second go at the head gaskets.

Oliver, I'm with Rob on this one. Head gasket failure on a KV6 is very unlikely and a warped head even less so.

Have you checked that your radiator fan slow speed is working? It's easy using the 'demist test'. If it isn't, the temperature gauge won't tell you until the engine has severely overheated and that's not good for head gaskets as you know.

Simon

arblickspule · 28th March 2019, 19:12

More and more encouraging.

The high speed was on when I stopped the car both times she overheated but no sign of the slow speed. As our temp gauges are less than reliable I've been monitoring the temp with an OBDII reader and, for the most part, it was hovering around mid to high 80's. Got complacent and stopped monitoring it this week. Doh!

This time though the radiator metal was icy cold so perhaps we didn't manage to clear all the blockages or maybe it's air locked. Will give her another coolant flush and oil change (is there an oil flushing method?) and replace the cooler. Watch this space.

Once again, thanks.

350zwelgje · 28th March 2019, 22:21

Replace a silver resistor for gold (Jules on here is a good supplier). Had to do this when I got the KV6.Think only overheating is about the only thing that can kill KV6s, besides no oil of course

.
Flushing is crucial, myself use orange juice (the clear cheap type) a couple of times, then water (a lot) and even after a year and replacing the coolant, oil was still visible a little bit..... Difficult to sell a Rover like that if you don't know, or a cheap buy

. The diesel has done over 100k after replacing the cooler and then it went again after three years! Standard bmw stuff, probably not manufactured by them.

Hope it works out, good engines these KV6s, mine has done230k kilometers and plan to use it for another 6 years and 100k at least, if they let us on the continent

Rob

arblickspule · 29th March 2019, 19:19

Limped her home this morning (apologies to everyone on the A303 at 6am) using some skilful coasting and careful temperature monitoring.

Got her front off drained the oil which seems a) To be clear of mayo and b) in plentiful supply so not a lot, if any, has made it's way in to the coolant. Could it be that the mayo is the old residual stuff from the previous episode?

Ah, the coolant, yes, drained that too. Got about a litre and a half of it out of the bottom hose which is not much considering how much we put in. And how much water I topped it up with this morning. And halfway through the journey. The question is, where did it all go?! We'll save that for a later investigation though.

This oil cooler is the metal lump in front of the sump, with the coolant hoses at each end and oil hoses on the back, right? If so, I can't seem to find it on Rimmer Brothers website. I can find the 1.8, Diesel and Automatic versions but not the manual petrol V6. Might just be being dense after a nightshift though.

On to the fan, it's the three speed without the resistors. We reckon the brushes are knacked as we can get mid and high speed by shorting the relevant wires. It's just the low speed that notoriously fails after 60k. This engine's on 170k.

Brushes ordered and fan rebuild will commence tomorrow.

As always, thanks for the help! It is greatly appreciated!!!

Sonic ZS · 29th March 2019, 21:28

I've recently rebuilt the top ends on a KV6 following an idler failure that subsequently bent all the inlet valves.

After a pretty meticulous rebuild, the engine immediately started showing signs of oil in the coolant & vice versa.

Thinking logically, the cross contamination started far too quickly following the rebuild....far too quick (in my opinion to be head gasket failure). It was also odd that both systems were mixing with each other.

So after some careful consideration, I eventually decided that the oil cooler could be leaking - oil being pumped into the coolant when running (at maybe 50psi), then coolant being pushed the other way on switch off (no oil pressure, but coolant now sitting at around 20psi).

Sure enough, on removing & pressure testing the cooler, it had a pinhole of corrosion under one of the internal end seals.

New cooler from Rimmers subsequently fitted, both systems flushed and no more problems.

Moral is.....check the easy stuff BEFORE stripping everything apart again....especially if your engine may have been run previously without antifreeze

28th March 2019, 09:35	#4
350zwelgje Avid contributor 75 KV6 2.5 3x Rover 75 CDT Join Date: Jan 2011 Location: Belgium Posts: 249 Thanks: 6 Thanked 34 Times in 33 Posts	Am thinking oil cooler issue originqlly as only oil in coolant, first time and this time (not head gaskets ) Had this oil cooler issue on a diesel and diesels are more known for it, but can happen to KV6 as well. It is an oil coolant heat exchanger in aluminium that can start to leak internally. Temporary by-pass is possible and you can see if the problem is cured. Perhaps it is not necessary to have a second go at the head gaskets. Will do my KV6 distribution belts in couple of months and will change this cooler for a new one just to be sure.... Rob __________________ 75 KV6 2.5 Sterling automatic, 3x 75 CDT (2 manual + automatic), MG ZT 190+, 620i, SD1 2300S, P6 2000SC & TVR 350i

28th March 2019, 22:21	#8
350zwelgje Avid contributor 75 KV6 2.5 3x Rover 75 CDT Join Date: Jan 2011 Location: Belgium Posts: 249 Thanks: 6 Thanked 34 Times in 33 Posts	Replace a silver resistor for gold (Jules on here is a good supplier). Had to do this when I got the KV6.Think only overheating is about the only thing that can kill KV6s, besides no oil of course. Flushing is crucial, myself use orange juice (the clear cheap type) a couple of times, then water (a lot) and even after a year and replacing the coolant, oil was still visible a little bit..... Difficult to sell a Rover like that if you don't know, or a cheap buy . The diesel has done over 100k after replacing the cooler and then it went again after three years! Standard bmw stuff, probably not manufactured by them. Hope it works out, good engines these KV6s, mine has done230k kilometers and plan to use it for another 6 years and 100k at least, if they let us on the continent Rob __________________ 75 KV6 2.5 Sterling automatic, 3x 75 CDT (2 manual + automatic), MG ZT 190+, 620i, SD1 2300S, P6 2000SC & TVR 350i

29th March 2019, 21:28	#10
Sonic ZS Posted a thing or two 75 Conn CDT Tourer, 75 Conn SE V6, 75 Conn V6, 75 Conn CDTi Tourer, ZS 180 Join Date: Jan 2014 Location: Devon Posts: 1,986 Thanks: 1,287 Thanked 963 Times in 534 Posts	I've recently rebuilt the top ends on a KV6 following an idler failure that subsequently bent all the inlet valves. After a pretty meticulous rebuild, the engine immediately started showing signs of oil in the coolant & vice versa. Thinking logically, the cross contamination started far too quickly following the rebuild....far too quick (in my opinion to be head gasket failure). It was also odd that both systems were mixing with each other. So after some careful consideration, I eventually decided that the oil cooler could be leaking - oil being pumped into the coolant when running (at maybe 50psi), then coolant being pushed the other way on switch off (no oil pressure, but coolant now sitting at around 20psi). Sure enough, on removing & pressure testing the cooler, it had a pinhole of corrosion under one of the internal end seals. New cooler from Rimmers subsequently fitted, both systems flushed and no more problems. Moral is.....check the easy stuff BEFORE stripping everything apart again....especially if your engine may have been run previously without antifreeze __________________

28th March 2019, 08:27	#3
arblickspule Newbie Rover 75 Saloon Join Date: Apr 2017 Location: Winchester Posts: 17 Thanks: 0 Thanked 8 Times in 3 Posts	Guessing at the moment, as she only broke down yesterday, that we, in all likelihood, botched the gasket job. Initially, when she conked out it were due to, literally, the whole cooling system being clogged with emulsified oil. It was thick and everywhere. Every pipe, every cavity in the engine block, everywhere! None in the oil though. So we stripped out manifolds and removed the heads, cleaned as best we could, and popped her back together with a new gasket, water pump, thermostat, radiator, etc. Now, bare in mind that we were actually only trying to see if it was worth salvaging. We never actually expected her to start again! She did, and ran, with a slightly rich Bank 1, for a month before glooping up again. This time there be mayo in the oil too. Its entirely possible that we misdiagnosed the original issue but would have had to break her apart to clean anyway. So, we're thinking we warped a head? Didn't really check to be honest as we weren't expecting any success. Anyhow, it's got to be done again, this time, without snow but with much more time on our hands. And much more experience.

28th March 2019, 11:09	#5
arblickspule Newbie Rover 75 Saloon Join Date: Apr 2017 Location: Winchester Posts: 17 Thanks: 0 Thanked 8 Times in 3 Posts	Interesting. Never considered that. It would be fab if it is that, nice and easy to get to! Will check that first before hoiking them heads off again! Think we had to break her apart last time anyway as the mayo was just everywhere. I can't even estimate how much we removed. Gallons? It was just awful. Got to get her home from Fleet before we can see. Thanks for the input!

28th March 2019, 19:12	#7
arblickspule Newbie Rover 75 Saloon Join Date: Apr 2017 Location: Winchester Posts: 17 Thanks: 0 Thanked 8 Times in 3 Posts	More and more encouraging. The high speed was on when I stopped the car both times she overheated but no sign of the slow speed. As our temp gauges are less than reliable I've been monitoring the temp with an OBDII reader and, for the most part, it was hovering around mid to high 80's. Got complacent and stopped monitoring it this week. Doh! This time though the radiator metal was icy cold so perhaps we didn't manage to clear all the blockages or maybe it's air locked. Will give her another coolant flush and oil change (is there an oil flushing method?) and replace the cooler. Watch this space. Once again, thanks.

29th March 2019, 19:19	#9
arblickspule Newbie Rover 75 Saloon Join Date: Apr 2017 Location: Winchester Posts: 17 Thanks: 0 Thanked 8 Times in 3 Posts	Limped her home this morning (apologies to everyone on the A303 at 6am) using some skilful coasting and careful temperature monitoring. Got her front off drained the oil which seems a) To be clear of mayo and b) in plentiful supply so not a lot, if any, has made it's way in to the coolant. Could it be that the mayo is the old residual stuff from the previous episode? Ah, the coolant, yes, drained that too. Got about a litre and a half of it out of the bottom hose which is not much considering how much we put in. And how much water I topped it up with this morning. And halfway through the journey. The question is, where did it all go?! We'll save that for a later investigation though. This oil cooler is the metal lump in front of the sump, with the coolant hoses at each end and oil hoses on the back, right? If so, I can't seem to find it on Rimmer Brothers website. I can find the 1.8, Diesel and Automatic versions but not the manual petrol V6. Might just be being dense after a nightshift though. On to the fan, it's the three speed without the resistors. We reckon the brushes are knacked as we can get mid and high speed by shorting the relevant wires. It's just the low speed that notoriously fails after 60k. This engine's on 170k. Brushes ordered and fan rebuild will commence tomorrow. As always, thanks for the help! It is greatly appreciated!!!