V8 cooling fan

seanw9288 · 21st June 2016, 16:22

Now i know they are the same as all the other engined ZT's but what i would like to know is the cooling fan characteristics on other peoples V8's.

i have just replaced the resistor and the cooling fan cuts in at low speed when the aircon is switched on and when cooling is needed to cool the water in traffic.

When the car is fully warm, and i stop/turn the engine off, upon returning (5-10minutes) start the engine, then the fan will cut in on full speed for about 3 minutes. ls this normal ? I have had the diagnostics up on the dash showing actual temperature (test7) and always has shown below 100'C

i was thinking the V8's have an ambient temperature control for the engine bay like the MG TF?

T-Cut · 21st June 2016, 17:34

It could be the heat soak effect. This is caused by the engine block having a large surfeit of heat when you turn it off. The heat migrates into the head coolant where it can superheat and would trip on high speed cooling. But the engine's turned off so nothing happens until you start it again. If the head is super hot, the fan will run for up to five minutes even if the ignition is turned off again. Doing that as a test would prove it.

On the other hand, it could be something quite different.

TC

seanw9288 · 21st June 2016, 17:55

ok thanks for that, no the fan never comes on when the engine has been shut down, just the fan likes to come on fast when fired back up after sitting even though test 7 is showing its not that hot. i must admit them big iron blocks are good for holding heat, even after 12 hours of being sat in my garage next day i can feel some warmth to the top hose

ceedy · 21st June 2016, 18:03

When I changed my 260's fan last year, the Original one I took off was marked KV6 ?.

Chris

seanw9288 · 21st June 2016, 21:37

Quote:

Originally Posted by ceedy

When I changed my 260's fan last year, the Original one I took off was marked KV6 ?.

Chris

yep mine has the same sticker

T16 · 21st June 2016, 22:45

Nothing surprises me. Lots of facelift V8s had the older 2 speed cooling fan also.

Each model is pretty much unique with the parts bin raids !!

kaiser · 22nd June 2016, 01:36

V6 V8, what difference does a couple of cylinders do among friends?

ceedy · 22nd June 2016, 08:04

deleted............

21st June 2016, 16:22	#1
seanw9288 Newbie MG ZT turbo & Zt V8 SE Join Date: Mar 2016 Location: Sittingbourne Posts: 26 Thanks: 1 Thanked 8 Times in 6 Posts	V8 cooling fan Now i know they are the same as all the other engined ZT's but what i would like to know is the cooling fan characteristics on other peoples V8's. i have just replaced the resistor and the cooling fan cuts in at low speed when the aircon is switched on and when cooling is needed to cool the water in traffic. When the car is fully warm, and i stop/turn the engine off, upon returning (5-10minutes) start the engine, then the fan will cut in on full speed for about 3 minutes. ls this normal ? I have had the diagnostics up on the dash showing actual temperature (test7) and always has shown below 100'C i was thinking the V8's have an ambient temperature control for the engine bay like the MG TF?

21st June 2016, 18:03	#4
ceedy This is my second home All Trophy Blue ,ZT260#50 , ZT CDTI Auto, ZR105+ and 1.8T Firefrost spoiling the Set . Join Date: Nov 2006 Location: Nr Sherborne But in Somerset.. Posts: 6,093 Thanks: 916 Thanked 1,214 Times in 768 Posts	When I changed my 260's fan last year, the Original one I took off was marked KV6 ?. Chris __________________ The Three Bloo's Wifey's Zr105, MY CDTI & 260 #50 and Number One sons 1.8T in Firefrost When I were a lad Zero to 142 in 10.25 secs at the Pod on my Blown Norton. 210 Kart Champ in 70's

22nd June 2016, 01:36	#7
kaiser This is my second home 75 Tourer 2.5 Auto, 1.8T, 75V8ZT Join Date: Jun 2007 Location: Johannesburg ZA Posts: 6,200 Thanks: 1 Thanked 859 Times in 613 Posts	V6 V8, what difference does a couple of cylinders do among friends? __________________ Worth his V8 in gold

22nd June 2016, 08:04	#8
ceedy This is my second home All Trophy Blue ,ZT260#50 , ZT CDTI Auto, ZR105+ and 1.8T Firefrost spoiling the Set . Join Date: Nov 2006 Location: Nr Sherborne But in Somerset.. Posts: 6,093 Thanks: 916 Thanked 1,214 Times in 768 Posts	deleted............ __________________ The Three Bloo's Wifey's Zr105, MY CDTI & 260 #50 and Number One sons 1.8T in Firefrost When I were a lad Zero to 142 in 10.25 secs at the Pod on my Blown Norton. 210 Kart Champ in 70's

21st June 2016, 17:34	#2
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,754 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	It could be the heat soak effect. This is caused by the engine block having a large surfeit of heat when you turn it off. The heat migrates into the head coolant where it can superheat and would trip on high speed cooling. But the engine's turned off so nothing happens until you start it again. If the head is super hot, the fan will run for up to five minutes even if the ignition is turned off again. Doing that as a test would prove it. On the other hand, it could be something quite different. TC

21st June 2016, 17:55	#3
seanw9288 Newbie MG ZT turbo & Zt V8 SE Join Date: Mar 2016 Location: Sittingbourne Posts: 26 Thanks: 1 Thanked 8 Times in 6 Posts	ok thanks for that, no the fan never comes on when the engine has been shut down, just the fan likes to come on fast when fired back up after sitting even though test 7 is showing its not that hot. i must admit them big iron blocks are good for holding heat, even after 12 hours of being sat in my garage next day i can feel some warmth to the top hose

21st June 2016, 22:45	#6
T16 I really should get out more....... ZT CDTi 135, ZT260SE Join Date: Feb 2011 Location: Dundee Posts: 2,877 Thanks: 10 Thanked 331 Times in 213 Posts	Nothing surprises me. Lots of facelift V8s had the older 2 speed cooling fan also. Each model is pretty much unique with the parts bin raids !!