Cooling Issues

[CPhoenix]

Hi guys,

I had my K11 March in for a water pump replacement on Friday after it exploded earlier last week.

Now on my trip into work this morning my rad fan came on after about 6 miles, being rather concerned about this I continued the rest of the way with heater on full blast with the windows down (hopefully this trick works with the Micras?). Once at work, popped the bonnet and had a feel of the top rad hose which was a little soft but cold. The Rad itself wasn't even remotely warm and leads me to believe 1 of three things;

1) Theres an air pocket in the cooling system not allowing the water to circulate
2) The thermostat is bust and not opening up when reaching the right temp
3) Despite have a new pump from the Garage, the pump still isn't working.

Also when I switched the engine off and opened the rad cap, there was quite abit of pressure there but no water coming out. At the same time I also noticed a strong bubbling noise coming from the engine near the top rad hose.

The questions are; have I missed anything? What other diagnoses can I perform in order to locate the problem? If it is the thermostat (strong possibility), could I easily replace it myself?

Cheers for any help you can give!

CP.

 

[frank]

cp

just an air pocket i would think, mine usually needs topping up for a couple of days, after being drained

 

[CPhoenix]

Cheers boss,

/scuttles out of the office with a watering can

Well, I've topped the car up before I set off home giving it time to heat up and use up the additional water. Got about 2 miles and the fan came on and didn't go off again. I put the heater on hot and kept it on until I got 1 mile from home, since I wanted to try without the heater, it was switch off and saw the heater rocket upto 5mm off the H at the top. Turning it back on and it dropped back to just over midway. Once I pulled up outside my house, I popped the bonnet again and the reservoir was spitting like a viper! (obviously not happy!)

Ive attempted to flush the rad following Fordy's instructions (here):

undo bottom rad hose *Done
take cap off *Done
drain coolant out *Done & hooked up the garden hose for a good blast
refit hose *Done
fill with coolant *Done & filled with De-ionised water
start car *Done
refill rad and put cap on *Done
heater on hot *Done
then hold revs at 3k for say a 1 minute or 2 *Done
then leave idling till it blows hot air and rad fan cuts in and out a few times *This is where I hit a problem
then your done

*After starting the car & revving for a while with the heater on full, the fan never kicked in - even after idling for 30 mins!
I switched the heater off, rad fan started after 5 mins, switched heater on and fan switched back off and didn't switch on again even after another 15 minutes. - Is this normal?

I'll go out after tea and have a scoot around town and see if I've still got the same problem.
Your thoughts?

Cheers

CP

 

[frank]

cp

perhaps your thermostat fears are founded eh, not the most accessible things on a cg tho

 

[CPhoenix]

Thanks for the reply Frank,

Been out and about in the Micra again, the temp seems to be bouncing up and down between H and the middle. For the last few miles it seem to be very high, when I got back whilst there wasn't any spitting from the reservoir there was the sound of bubbling again coming from the top hose.

Can't think of much else that's would be causing this other than the thermostat.... so any recommendations if I do it myself?

Thanks.

 

[frank]

cp

there,s some info here
http://k11wiki.com/index.php?title=Thermostat

 

[capnmchl]

Sort of had this problem in a Mondeo back in July.

What had happened was, driving through town, the temperature gauge just shot right up, but the engine didn't feel particularly hot. Anyway, we took it down to the garage, and the mechanic found the problem right away.

Cracked thermostat casing. Basically, all the coolant pases through the thermostat casing, and if you get a crack in it, air gets in. Air heats up much quicker then coolant, so the thermostat gives a very hot reading, but the engine isn't actually overheating.

Had to buy a new thermostat, and casing. Problem solved.

 

[CPhoenix]

Fantastic stuff guys,

Right tomorrow, I'll order a new thermostat from the Nissan garage up the road. Whip the dizzy off and see how much WD40 I'll be needing on the thermostat casing - a lot, expect :grinning:
Any words on what type of sealant I'll need?

 

[rlees85]

id be careful driving around until its fixed. getting the coolant bubbling can really brake things...

as for what it is i agree with whats been said.. thermostat/dodgy pump again.

 

[CPhoenix]

id be careful driving around until its fixed. getting the coolant bubbling can really brake things...

as for what it is i agree with whats been said.. thermostat/dodgy pump again.

I think thats why my water pump went in the first place - I wont be driving it again until its fixed. ((Un)Luckily my cyborg hasn't sold yet).

 

[CPhoenix]

Another quick question, would RTV sealant be okay to use on the thermostat casing?

 

[CPhoenix]

Thanks to frank, rlees85 and capnmchl - just thought I'd give a quick update:

Replaced the thermostat, easy job
Used RTV sealant on both the thermostat lip and the housing, which has done the job pretty well.
When I first started the car I got rather worried as bottom rad hose didn't get warm at all (despite the top hose getting hot), eventually it yielded and the fan now kicks in and out as expected. Even after a blast around last night and the trip into work this morning no problems so far... touch wood.

Fingers crossed this is hopefully the end of my cooling problems :laugh:
Happy days, Cheers guys