Warning! Some V6 engines can be very dangerous in cold weather. Problem can be solved

robwijnstok · 1st February 2012, 20:48

Situation
Imagine you are in a city or on a motorway and suddenly a Cruise Control is spontaneously engaged and you cannot switch it off, even when you have no Cruise Control this can happen! If you depress the clutch (or put your autobox in neutral) the revs are getting sky high up to the ‘red zone’.
Here the story and solution…

My 75 had in winter 2009/2010 and 2010/2011 a very scary and dangerous habit when I was driving it at -4°C or cooler. If the engine was revved more than 2000rpm at this temperature for just a second the engine was keeping the revs on the highest value of that moment and there was no way of revving down the engine except by shutting it off with the key. After that, I had to stop the car, and had to wait for 3 to 5 minutes (if the engine is already warm), and after starting all is fine until I hit 2000rpm again. When I kept the revs lower than 2000rpm all was fine and I could drive for hours if I wanted.

There was an earlier post by member Vulcan69 who experienced the same problem, but also others had this problem. See the thread of Vulcan69 here for mine and other members posts https://www.the75andztclub.co.uk/forum/showthread.php?t=33068&highlight=winter+gremlin

This morning I drove at -8°C with 3000rpm and had no problem anymore!

Analysis
In the Netherlands Richard van Noort http://www.autobedrijfvannoort.nl/ (website mentioned with his permit) is known as problem solver when there are complicated problems with Rover or MG cars. I see Richard as the Dutch ‘Lates’. When I phoned Richard and told him about my problem, he had a hunch that it could have something to do with the breathing of the rocker covers. I visited him, and after a minute or so he was convinced. Bad breathing of the rocker covers! Cause was contamination on the inside of the engine especial the two filters in the rocker covers. Both filters and also the small breather hole of the front rocker covers were blocked up completely. The larger breather hole of the front rocker cover, and the breather hole of the back rocker cover were almost blocked. This caused that there was lots of sludge and WATER dripping into the throttle body see my pictures in the Winter Gremlin posts.

Checklist
for your engine if you have the same sort of problems;
- An easy way to check is the oil filler cap, inside should be clean, more or less like new and dry.
- Check with a finger through the oil filler hole on the inside of the rocker cover. If you press and scrape with your nail on the inside it should be clean also. You should not find a hard tuff coat what looks like very dark brown or black dirt.
- If you look from the side of the airbox through the hole inside the rocker cover you can just see one of the metal filters if it is completely black, that could be a sign also.
- Last but not least check the inside of the throttle body. A bit of oil is normal, sludge or water (especially water) is NOT a good sign.

Solution
what worked instantly for me;
- Clean both rocker covers inside especial the breather holes behind the metal filters. Each side took me an hour working with petrol, screw drivers and metal wool. Cleaned small breather hole with a paper clip. Large ones carefully with a screw driver.
- Replace metal rocker cover filters with new ones.
- Clean breather pipes inside with compressed air, or replace with a new one.
- Clean throttle body inside.
- We did a engine flush with Forté engine flush to clean the rest of the inside of the engine. And filled the engine with Mobile 3000 X1 5W40 full synthetic oil and added a bottle of Forté Top End Treatment what will help to clean the engine while driving.
- After 1500km (940miles) we did a flush and new oil (Mobile 3000) again.

Apologies
The solution on the car was done by Richard van Noort on the 4th of April 2011, but after that date it was not cold enough anymore to have proof that this was the 100% solution. This is the reason for me to put this tread on the forum not sooner then today. Today I drove at -8°C with 3000rpm for a while and had no problem at all that was my 100% proof.
I did not wanted to scare any people while no real proof of cause and solution until it was there for me. So to the people who experienced this problem in between and had have some close encounters I am sorry, but hope you understand my point of view also.

Probable cause and advise
When I was for the first analysis at Richard van Noord he had organized a technical specialist from Forté. This specialist had seen lots of similar problems with other main car brands. The overall drawn conclusion is that car manufacturers delayed the services and oil changes of engines more and more. 25.000km (15.500miles) what Rover had as service and oil change interval is too long, and engines can contaminate because of that. Also the use of a good brand oil and an oil change at maximum of 15.000km (9.375miles) was recommended to me. Since I do 18.000km (11.250miles) a year I will change my oil every 6 months now.

Compliments
To Stocktake who was on the right way with his thinking. I don’t see the use of a catch tank anymore because the reason for a catch tank is taken away by Richard van Noort. At the last check of my throttle body at Richard a couple of weeks ago there were only a few drops of oil what was a normal amount according to Richard. The metal filter what is visible inside the front rocker cover was still clean.

Dirty 3 (Medium).JPG

Dirty 2 (Medium).JPG

Dirty 1 (Medium).JPG

Cleaned 1 (Medium).JPG

Little hole text (Medium).JPG

Rob.

stocktake · 1st February 2012, 21:05

Meant to ask you the outcome of this Rob, glad your sorted and a great write up

Ben (typhoon 190) has had similar problems with these filters

Another to put on the list

Canonite · 1st February 2012, 21:15

Sometimes when I start my car cold it will rev high at 2000rpm and takes ages to come down. I just thought that was down to the idle air valve on the throttle body.
I have to warm the car up in the works yard as in first gear the engine is running too fast to negotiate the speed humps so I have to take it out of gear.

jn12 · 1st February 2012, 21:16

Hi Rob,

I also had blocked breathers in the rocker covers. Similar to yours except my cams looked a bit cleaner then yours

I soaked my covers in Gunk over night and sprayed all the breather pips with carb cleaner.

This did not cause any problems with the throttle or running of the engine though , I would think this would be more down to lubrication of the throttle cable.

See thread http://www.the75andztclub.co.uk/foru...ad.php?t=99064

John

jn12 · 1st February 2012, 21:18

Quote:

Originally Posted by Canonite

Sometimes when I start my car cold it will rev high at 2000rpm and takes ages to come down. I just thought that was down to the idle air valve on the throttle body.
I have to warm the car up in the works yard as in first gear the engine is running too fast to negotiate the speed humps so I have to take it out of gear.

I had this after adjusting my throttle cable too tight, back a few turns and it has been fine ever since

John

robwijnstok · 1st February 2012, 21:20

Quote:

Originally Posted by stocktake

Meant to ask you the outcome of this Rob, glad your sorted and a great write up

Ben (typhoon 190) has had similar problems with these filters

Another to put on the list

Hi Dave,

The first time it happened to me I was driving on the motorway at 120km (75miles) of speed with my real cruise control on! When I exited the motorway my car could not be stopped, and I had only a couple of hundreds of meters to figure out what the hell was going on, and stop. It went just well but it scared the living daylights out of me.
I have had my portion of close encounters, believe me… not one of them was fun.

Now there was a proven solution for me I would share this as complete as I can. If there is even just one 75 or MG with the same problem as I had, and the same solution works for that car too, makes all the writing worth for me.

Rob.

robwijnstok · 1st February 2012, 21:25

I lubricate my throttle cable with a couple of cc's of PTFE (teflon) spray, see this post http://www.the75andztclub.co.uk/foru...2&postcount=31
Works fine for me.

bl52krz · 1st February 2012, 21:36

Hi. Real good write up. Will have to tell my son to be careful,he has a kv6.

craig8661 · 2nd February 2012, 08:22

was going to say my friend with a ford scorpio had a sticking throttle body so took it apart cleaned it and all was ok for anouther year cant remember if his was the v6 or v8 but it was a auto he burnt the pads and disks out on the front after he over took a lorry and it kepted going

COLVERT · 2nd February 2012, 10:13

So the throttle was sticking at temperatures below freezing point and you say water was the problem...
Was the water turning to ice which then held the throttle open in whatever position it happened to be at at the time ??? ( Dripping into the throttle body, you say. )
Above freezing point there was no problem, ie. no icing up ???

1st February 2012, 20:48	#1
robwijnstok Gets stuck in Rover 75 Tourer 2.5V6 autobox, Rover Streetwise 2.0 DTi, MG ZR160 Join Date: Oct 2007 Location: Gelderland Posts: 617 Thanks: 5 Thanked 16 Times in 15 Posts	Warning! Some V6 engines can be very dangerous in cold weather. Problem can be solved Situation Imagine you are in a city or on a motorway and suddenly a Cruise Control is spontaneously engaged and you cannot switch it off, even when you have no Cruise Control this can happen! If you depress the clutch (or put your autobox in neutral) the revs are getting sky high up to the ‘red zone’. Here the story and solution… My 75 had in winter 2009/2010 and 2010/2011 a very scary and dangerous habit when I was driving it at -4°C or cooler. If the engine was revved more than 2000rpm at this temperature for just a second the engine was keeping the revs on the highest value of that moment and there was no way of revving down the engine except by shutting it off with the key. After that, I had to stop the car, and had to wait for 3 to 5 minutes (if the engine is already warm), and after starting all is fine until I hit 2000rpm again. When I kept the revs lower than 2000rpm all was fine and I could drive for hours if I wanted. There was an earlier post by member Vulcan69 who experienced the same problem, but also others had this problem. See the thread of Vulcan69 here for mine and other members posts https://www.the75andztclub.co.uk/forum/showthread.php?t=33068&highlight=winter+gremlin This morning I drove at -8°C with 3000rpm and had no problem anymore! Analysis In the Netherlands Richard van Noort http://www.autobedrijfvannoort.nl/ (website mentioned with his permit) is known as problem solver when there are complicated problems with Rover or MG cars. I see Richard as the Dutch ‘Lates’. When I phoned Richard and told him about my problem, he had a hunch that it could have something to do with the breathing of the rocker covers. I visited him, and after a minute or so he was convinced. Bad breathing of the rocker covers! Cause was contamination on the inside of the engine especial the two filters in the rocker covers. Both filters and also the small breather hole of the front rocker covers were blocked up completely. The larger breather hole of the front rocker cover, and the breather hole of the back rocker cover were almost blocked. This caused that there was lots of sludge and WATER dripping into the throttle body see my pictures in the Winter Gremlin posts. Checklist for your engine if you have the same sort of problems; - An easy way to check is the oil filler cap, inside should be clean, more or less like new and dry. - Check with a finger through the oil filler hole on the inside of the rocker cover. If you press and scrape with your nail on the inside it should be clean also. You should not find a hard tuff coat what looks like very dark brown or black dirt. - If you look from the side of the airbox through the hole inside the rocker cover you can just see one of the metal filters if it is completely black, that could be a sign also. - Last but not least check the inside of the throttle body. A bit of oil is normal, sludge or water (especially water) is NOT a good sign. Solution what worked instantly for me; - Clean both rocker covers inside especial the breather holes behind the metal filters. Each side took me an hour working with petrol, screw drivers and metal wool. Cleaned small breather hole with a paper clip. Large ones carefully with a screw driver. - Replace metal rocker cover filters with new ones. - Clean breather pipes inside with compressed air, or replace with a new one. - Clean throttle body inside. - We did a engine flush with Forté engine flush to clean the rest of the inside of the engine. And filled the engine with Mobile 3000 X1 5W40 full synthetic oil and added a bottle of Forté Top End Treatment what will help to clean the engine while driving. - After 1500km (940miles) we did a flush and new oil (Mobile 3000) again. Apologies The solution on the car was done by Richard van Noort on the 4th of April 2011, but after that date it was not cold enough anymore to have proof that this was the 100% solution. This is the reason for me to put this tread on the forum not sooner then today. Today I drove at -8°C with 3000rpm for a while and had no problem at all that was my 100% proof. I did not wanted to scare any people while no real proof of cause and solution until it was there for me. So to the people who experienced this problem in between and had have some close encounters I am sorry, but hope you understand my point of view also. Probable cause and advise When I was for the first analysis at Richard van Noord he had organized a technical specialist from Forté. This specialist had seen lots of similar problems with other main car brands. The overall drawn conclusion is that car manufacturers delayed the services and oil changes of engines more and more. 25.000km (15.500miles) what Rover had as service and oil change interval is too long, and engines can contaminate because of that. Also the use of a good brand oil and an oil change at maximum of 15.000km (9.375miles) was recommended to me. Since I do 18.000km (11.250miles) a year I will change my oil every 6 months now. Compliments To Stocktake who was on the right way with his thinking. I don’t see the use of a catch tank anymore because the reason for a catch tank is taken away by Richard van Noort. At the last check of my throttle body at Richard a couple of weeks ago there were only a few drops of oil what was a normal amount according to Richard. The metal filter what is visible inside the front rocker cover was still clean. Dirty 3 (Medium).JPG Dirty 2 (Medium).JPG Dirty 1 (Medium).JPG Cleaned 1 (Medium).JPG Little hole text (Medium).JPG Rob. __________________ [SIGPIC][/SIGPIC] Membership Number 344 Driving with a BIG smile... and it's Chatsworth Elegant Bronze. Never drive faster than your guardian angel can fly! Last edited by Dragrad; 29th December 2014 at 23:31.. Reason: Thumbnails enlarged

1st February 2012, 21:05	#2
stocktake Vis Whiz Rover 75 2.5 auto Saloon Join Date: Jun 2007 Location: LEEDS Posts: 20,591 Thanks: 2,057 Thanked 3,056 Times in 1,621 Posts	Meant to ask you the outcome of this Rob, glad your sorted and a great write up Ben (typhoon 190) has had similar problems with these filters Another to put on the list __________________ Dave... Lost a few stones and a Gall Bladder and part of a bile duct and all of my dignity in the suppository incident

1st February 2012, 21:16	#4
jn12 Gets stuck in MG ZT SE 180 V6 Sports Auto Join Date: Dec 2006 Location: Newcastle upon Tyne Posts: 938 Thanks: 74 Thanked 37 Times in 36 Posts	Hi Rob, I also had blocked breathers in the rocker covers. Similar to yours except my cams looked a bit cleaner then yours I soaked my covers in Gunk over night and sprayed all the breather pips with carb cleaner. This did not cause any problems with the throttle or running of the engine though , I would think this would be more down to lubrication of the throttle cable. See thread http://www.the75andztclub.co.uk/foru...ad.php?t=99064 John Last edited by jn12; 1st February 2012 at 21:25..

1st February 2012, 21:25	#7
robwijnstok Gets stuck in Rover 75 Tourer 2.5V6 autobox, Rover Streetwise 2.0 DTi, MG ZR160 Join Date: Oct 2007 Location: Gelderland Posts: 617 Thanks: 5 Thanked 16 Times in 15 Posts	I lubricate my throttle cable with a couple of cc's of PTFE (teflon) spray, see this post http://www.the75andztclub.co.uk/foru...2&postcount=31 Works fine for me. __________________ [SIGPIC][/SIGPIC] Membership Number 344 Driving with a BIG smile... and it's Chatsworth Elegant Bronze. Never drive faster than your guardian angel can fly!

1st February 2012, 21:36	#8
bl52krz This is my second home Rover 75 cdt club + Rover 2.5 KV6 Conni SE Join Date: May 2008 Location: Birmingham Posts: 11,394 Thanks: 6,587 Thanked 2,262 Times in 1,729 Posts	Hi. Real good write up. Will have to tell my son to be careful,he has a kv6. __________________ Great Barr, Birmingham.

1st February 2012, 21:15	#3
Canonite This is my second home BMW 330d Tourer, MG ZT 180 SE XPG, VW Polo 6R 1.2 TDI Bluemotion Join Date: Jul 2011 Location: York Posts: 6,022 Thanks: 363 Thanked 574 Times in 319 Posts	Sometimes when I start my car cold it will rev high at 2000rpm and takes ages to come down. I just thought that was down to the idle air valve on the throttle body. I have to warm the car up in the works yard as in first gear the engine is running too fast to negotiate the speed humps so I have to take it out of gear.

2nd February 2012, 08:22	#9
craig8661 Posted a thing or two rover 75 tourer cdt Join Date: Feb 2011 Location: Chesterfield Posts: 1,924 Thanks: 3 Thanked 4 Times in 4 Posts	was going to say my friend with a ford scorpio had a sticking throttle body so took it apart cleaned it and all was ok for anouther year cant remember if his was the v6 or v8 but it was a auto he burnt the pads and disks out on the front after he over took a lorry and it kepted going __________________ http://i984.photobucket.com/albums/a...y%20se/sig.jpg spoilt as i own a cdt auto connoisseur se cdt auto member 829 mods so far synergy 2 heated washer jets cant really add anything else as it has it all lol

2nd February 2012, 10:13	#10
COLVERT This is my second home R75 Saloon. Join Date: Feb 2009 Location: France/or Devon. Posts: 14,003 Thanks: 3,851 Thanked 2,167 Times in 1,816 Posts	So the throttle was sticking at temperatures below freezing point and you say water was the problem... Was the water turning to ice which then held the throttle open in whatever position it happened to be at at the time ??? ( Dripping into the throttle body, you say. ) Above freezing point there was no problem, ie. no icing up ???