|
||
|
21st August 2020, 22:35 | #1 |
Avid contributor
MG ZT Join Date: Sep 2014
Location: Westhoughton Bolton
Posts: 233
Thanks: 153
Thanked 16 Times in 14 Posts
|
Fan struggling to reduce temperature unless revved kv6
Hi further to my cooling system problems the fan is taking a long time to reduce the temperature from 100 to 95 when this temperature is reached sometimes the bottom hose will go Luke warm and the top hose warm but you can squeeze it easy enough here's the thing when I rev the engine the top will go harder and the bottom hose will get hot again with the temperature dropping down to about 90. Also sometimes when I undo the coolant tank cap when it's cold a couple of big air bubbles come through the bleed hose hole whilst sometimes the level is higher than what it was the previous day if I leave the cap off a minute the level will drop in the tank. Also when the fan comes on you can smell like hot coolant odour been wafted around I have checked the radiator which is not leaking and I have recently renewed the lower coolant rail. When I start the car from cold with the cap off and rev it the coolant will rise to the top within about 30 seconds. Me and my friend think exhaust gases are going in the cooling system even though there is no bubbles in the coolant when it rises and no pressure release when I undo the cap.
Thanks. Forgot to mention the coolant backing up in the expansion tank has only happened since I replaced the oil cooler. Last edited by racing green rover; 21st August 2020 at 22:44.. Reason: More info |
21st August 2020, 22:47 | #2 |
This is my second home
Rover75 and Mreg Corsa. Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,753
Thanks: 341
Thanked 3,660 Times in 2,924 Posts
|
The most likely issue is an air lock in the cooling system. Revving the engine encourages it to move and a partial coolant circulation occurs. This explains the temperature variation in the hoses. The first thing to do is to bleed and top up the system using the 'official' procedure. You can easily locate it using the forum search system, or read the Haynes manual which contains the same info. When all the air's been eliminated, any further problem diagnosis will be a lot easier.
TC |
21st August 2020, 22:54 | #3 |
Avid contributor
MG ZT Join Date: Sep 2014
Location: Westhoughton Bolton
Posts: 233
Thanks: 153
Thanked 16 Times in 14 Posts
|
Thanks I already used the correct bleeding method provided by the forum however when I was in process of doing it one of the rubber coolant hose clips which connects to the lower coolant rail was leaking which I have now fixed so could be that? I'll try re bleeding it
Thanks |
22nd August 2020, 14:15 | #4 |
This is my second home
Rover75 and Mreg Corsa. Join Date: Nov 2006
Location: Sumweer onat mote o'dust (Sagin)
Posts: 21,753
Thanks: 341
Thanked 3,660 Times in 2,924 Posts
|
Yes, coolant leaks out and is replaced with air. The air may become locked if you simply keep topping it up.
TC |
23rd August 2020, 00:16 | #5 |
NI/ROI RS
ZT-T 190 / 75 Diesel x3 / 6 door limo / 216 Cabby / Rover 25 van Join Date: May 2009
Location: Antrim
Posts: 8,103
Thanks: 299
Thanked 1,046 Times in 568 Posts
|
Had exact issue on a 2.5 v6 auto, turned out the plastic impeller on water pump had shattered and wasn't working effectively.
__________________
Cheers, Colin Robson Rover Repair on Youtube DISCOUNTED MTEC BRAKES FOR ALL MG ROVER'S Braided hoses, more coating and pad options for 2024 |
23rd August 2020, 08:50 | #6 | |
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,378
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
Quote:
Did you follow the MG Rover refilling and bleeding procedure afterwards? KV6 cooling system: filling and bleeding. Simon
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. |
|
23rd August 2020, 13:10 | #7 |
Avid contributor
MG ZT Join Date: Sep 2014
Location: Westhoughton Bolton
Posts: 233
Thanks: 153
Thanked 16 Times in 14 Posts
|
Hi Simon yes I did although one of the quick release connectors from the rubber pipe to the lower coolant rail wasn't gripping enough so water was leaking as I was in the process of bleeding it I'm going to rebleed it tomorrow and report back on results. I checked the top hose earlier and you could easily squeeze it there was no flow through it even though it was hot
|
23rd August 2020, 17:52 | #8 | ||
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,378
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
Quote:
Quote:
Has this engine ever had K-seal (or similar) added to the cooling system? Simon
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. |
||
23rd August 2020, 20:10 | #9 |
Avid contributor
MG ZT Join Date: Sep 2014
Location: Westhoughton Bolton
Posts: 233
Thanks: 153
Thanked 16 Times in 14 Posts
|
No the thermostat isn't leaking I've checked it and also replaced it last year, as for the top and bottom hoses I was being vague with the temperature they was just warm you could easily hold them for ages you can easily squish them when the engine is hot it's as if it's lost pressure and the maximum temperature was 103 when the fan was on slightly dropping to 102 and dropping all way to 87 when I hold revs at 3000 rpm. The engine had k seal in it when I bought it 18 month ago but I've flushed it countless of times and used a few bottles of flush if you look at the thread 'looking at buying a contemporary se v6' that's the same vehicle.
Cheers Last edited by racing green rover; 23rd August 2020 at 20:34.. |
23rd August 2020, 21:32 | #10 | |
Doesn't do things by halves
Rover 75 2.5 Connoisseur Auto (1999) Dealer launch model. Join Date: Mar 2007
Location: Former Middlesex
Posts: 20,378
Thanks: 1,587
Thanked 3,749 Times in 3,181 Posts
|
K-seal
Quote:
As for your radiator hoses, they both should feel too hot to hold. I remember one member found that his oil cooler was blocked with K-seal. Maybe you have this too or perhaps your radiator channels are similarly affected. I'm afraid the only way to find out is to physically check suspect components. Have you disconnected the top and bottom radiator hoses and tested flow with a hosepipe? Simon
__________________
"Whatever is rightly done, however humble, is noble." Sir Henry Royce. |
|
|
|