Hippo

Hippo

Lord Hippo
This is a serious fred. Don't start giving me the usual crap.

Should the coolant pipe arrowed below with the number 8 be cold after a 3.5 mile trip this evening when the outside temp was about 5 degrees, and the engine started from cold?

Speed was 60mph for 2.5 miles, 30 to 40mph for 1 mile.

I assume not so the thermostate or water pump int doing it's job? (or worse :eek:)

With the engine running on tick over water was pumping into the coolant reservoir. Water level was normal, a little higher than when it's cold. Top radiator pipe was hot. When I undone the coolant reservoir top the water went up by 2 inches and stayed at that height.

cgqcYv2.jpg

coolingv6 cgqcYv2
 
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Surely it should be colder than the rest of the system as its been through the rad? As above, try a longer run and see if the thermostat opens and the water in that pipe is warmer.
 
The Mad Hat Man said:
was the coolant bottle bubbling?
loosing any water?
yes it should be cold.
Click to expand...
Not bubbling. No water loss other than a mug full every year.

As a bove I was wondering if the cold air was more than enough to keep the rad output pipe water cool. Thing is the pipe is cold tap water cold. That got me thinking somethings up as I noticed recently it heats up very quick and the heater inside gets warm quicker too. I know the kv6 runs hotter and keeps the stat closed until needed but I nearly pooped meself when feeling the pipe.

When have my hawkeye plugged in tomorrow to see what the temp gets to.
 
if it helps which it might not :p my 300tdi in this weather doesn't even get up to half way when doing 70!

If I'm pottering round town the gauge barely moves off the C but it sits nicely just under half in summer even when its roasting at 25* outside! Brand new rad in it though and it has been about 2* outside round here………well between -4 and 8* depending on day but most have been 1.5* - 2*
 
paranoia is a wondrous thing :eek:.

i wouldnt worry too much. very cold air temp on an overcooled system.
 
Once started let the engine idle until the bottom hose warms up. The cooling effect of moving forward takes huge amounts of heat out the rad. Or if you drive the car, get the engine revs over 4.5k as that will open the PRT allowing the water to circulate but bear in mind if you are moving then the air will cool the hot water again ;)
 
As Nodge says, if there's one thing I've learned during all my cooling adventures it's that modern radiators are extremely good heat exchangers. Your thermostat will be regulating the flow of all that abundant cold water if it's doing it's job properly.

Get yourself an infrared thermometer gun and take point temps around the system, you can easily find a block just by seeing a sudden temp change. But if you've been going 60 then I'd reckon that in this freezing weather the bottom hose will be fooking cold. My EWP is only barely above minimum RPM in these conditions as there is such a massive amount of cold water for it to play with. Saves alot of power and my fuel consumption seems to have actually improved in the cold weather!!
 
Thanks all. Will check hawkeye temp and infra red temp tomorrow on a 30mph dirve long enough to warm it up and report back. :eek:
 
I tested the my hose temps and engine live data on my commute this morning. The results are this. Top hose 80°C Bottom hose 18°C and the live data showed 99°C. The commute was 7 miles 5 miles at 40-50 mph with the last 2 miles at 30 mph or less with a couple of stops at traffic lights. The air temp was 6°C.
So what you have discovered is normal as I initially thought.

Edit
Don't forget that the thermostat doesn't open in response to bottom hose temp even though that's what it controls. The thermostat is sensing the water temp in the heater/cooler return which is less likely to be completely cold even in very cold conditions.
 
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Thanks all.

Tried testing it this morning and struggled to get it hot enough at low speeds with higher than normal revs by manually selecting gears. Got the top hose hot to 85+ degrees and bottom hose still cold. Thinking about it the water pump must still be running as it's pumping water into the coolant tank but forgot about that last night. Time was pushing on so I gave up and went to work. Checked bottom pipe again and it was just starting to warm up. Hawkeye coolant readings from the computer and infra red measured pipe temps were similar to nodge68's in post 13 above. So with it being cold I gave up. The stress of potentially losing ma hippo got to me last night. Still a bit worried with it on me mind this morning I even pulled up to an island and put the clutch in.

Had another go after work and warmed it up while driving slowly. Went to a hiding spot where I could sit a 2000 revs in peace and the top pipe got hot and the bottom pipe followed it when the coolant got hot enough for the stat to open. Watched the temp go up and the radiator was hot all over. Bottom pipe was something like 75 degrees. Got it so hot that the fans switched on at 109 degrees coolant temp on me hawkeye. Fans stopped as the temp passed 106 degrees. Hawkeye coolant temp dropped to about 102 degrees before starting to slowly rise again.

In conclusion all is well and I loves ma hippo again. Frightening to think I could lose him after all the good times we've had but a good eggsperience and a chance to check everything is ok. I loves ma hippo I does. He makes me happy. :)
 
It's very difficult to get a modern cooling system hot when the weather is cold as the rad is just to good at getting rid of heat. Although the bottom hose and the water in it is cold the stat is working correctly. It's opening in response to engine temp but instead of flooding the engine with cold water, it's allowing just enough into the engine to keep it temp constant to within a couple of ° which is how the system has been designed to work ;)
I'm glad all is well and you still love the Hippo !!
 
Was thinking today it's about time it had its coolant changed. Got 4L of oats already from the stealer. Looked in the rave and it ses:

remove the reservoir cap
drain using the cylinder drain plug (bottom front of engine) and remove the bottom hose from the radiator and allow system to drain
flush with none pressured cold water
fit cylinder drain plug
fit bottom hose to radiator
prepare coolant mix (50% oats 50% water)
set heater control to max
remove bleed screw from heater return pipe (rear of engine)
fill system until a steady flow from the bleed screw appears
fit bleed screw cap
fit reservoir cap
start and run engine until up to normal temp (don't run air con)
check for warm air at the vents
switch off engine and allow to cool and check for leaks and top up reservoir to max level

Am I correct in assuming the flush water enters the system via the coolant reservoir? If the engine is cold then I'm thinking the stat will be closed and water won't flow into the radiator. Should I remove the top hose on the radiator to flush the radiator?
 
Nodge68 said:
It's very difficult to get a modern cooling system hot when the weather is cold as the rad is just to good at getting rid of heat. Although the bottom hose and the water in it is cold the stat is working correctly. It's opening in response to engine temp but instead of flooding the engine with cold water, it's allowing just enough into the engine to keep it temp constant to within a couple of ° which is how the system has been designed to work ;)
I'm glad all is well and you still love the Hippo !!
Click to expand...

on a 3 mile trip no, drive the fooker 20 miles and it will be upto temp:rolleyes:
 
Thor1950 said:
on a 3 mile trip no, drive the fooker 20 miles and it will be upto temp:rolleyes:
Click to expand...

There are to many variables involved to say that ;) The KV6 is at running temp within 2 miles even if the air temp is below freezing but the bottom hose would still be cool after a 50 drive as there is no need for all the rad's capacity !!
 
Hippo said:
Was thinking today it's about time it had its coolant changed. Got 4L of oats already from the stealer. Looked in the rave and it ses:

remove the reservoir cap
drain using the cylinder drain plug (bottom front of engine) and remove the bottom hose from the radiator and allow system to drain
flush with none pressured cold water
fit cylinder drain plug
fit bottom hose to radiator
prepare coolant mix (50% oats 50% water)
set heater control to max
remove bleed screw from heater return pipe (rear of engine)
fill system until a steady flow from the bleed screw appears
fit bleed screw cap
fit reservoir cap
start and run engine until up to normal temp (don't run air con)
check for warm air at the vents
switch off engine and allow to cool and check for leaks and top up reservoir to max level

Am I correct in assuming the flush water enters the system via the coolant reservoir? If the engine is cold then I'm thinking the stat will be closed and water won't flow into the radiator. Should I remove the top hose on the radiator to flush the radiator?
Click to expand...

Yes all water enters the system via the tank ;) The block drain is on the front of the engine below the exhaust manifold at the gearbox end ;)
Edit
Don't start the engine until you know it's almost full as the HG'S are easily cooked by airlocks. I change the stat when I do the coolant as a precaution against future leaks too!!
 
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