coolant change / flush?

oh mighty org, I have a 07 plate sk6. I'm getting some temp guage fluctuations. Nothing major, it just seems to hunt between 80 and 87 during normal running. I thought that a coolant change and flush may help as i haven't done it yet nor had the previous owner. I've got a haynes manual so i'm gonna follow that. Do I need to use a flush agent and whats the best to use. Anybody got any other tips or pitfalls to watch for?

och aye the noo

Scotty

[MJC-DEV]

That's a pretty normal range of temperatures to see. It can be even more in colder weather or depending on speed, traffic etc.
Manual says change after 4 years so good to do but it won't make any difference to temperature fluctuation you see while driving.
Lots of video guides on SVRider. I wouldn't bothering with flushing chemicals, just hose out and re-fill with distilled water/Glycol mix (any brand).
Tip: The bucket needss to be further away than you think from the drain hole.

[embee]

I'll second everything said above. You will see some fluctuations with a "thermostat-on-outlet" design, the only time you don't is when the temps are generally above the fully open temp for the stat, which under normal conditions you won't generally achieve except when stationary.

Thermostats aren't open or closed, they start to open at a certain temp (perhaps 88C or so) and reach fully open at somewhat higher (maybe another 5C or similar). When they start to open they let coolant through to the rad, the coolant already in the rad goes into the engine but of course this is pretty cool, so it pulls the engine temp down and when it reaches the 'stat it causes it to close a bit which reduces the flow to the rad until the coolant heats up again, and so it cycles.

Quite a lot of cars use a thermostat-on-inlet, where they regulate the flow in from the rad, generally speaking these give much more stable control and minimise the temp fluctuations.

[muzikill]

Originally Posted by MJC-DEV

Tip: The bucket needs to be further away than you think from the drain hole.

Think wee wee distance btw !

[mep]

Originally Posted by muzikill

Think wee wee distance btw !

Too right, even I was suprised.

There is a photo in the Haynes manual, but you can't see the bucket.

Thanks for all the help. I'll be flushing as soon as i can.

Thanks again

Scotty

[mep]

For what it's worth I did mine a few weeks ago followijg the Haynes manual and used Holts Speedflush (only once, not twice as suggested in the Haynes manual) and topped up with ready mixed Halfords antifreze and coolant concentrate, the blue one that lasts for 2 years.

The next fun bit is disposing of the old stuff and flushed fluid!

mep how did you get on? I read some reviews of flush agents, and there are some dodgy instructions out there apparantly. Like flushing a hot engine with cold water or flush agent - but the haynes does say to let the engine cool. Anyway I'd be interested to know.

[mep]

Scotty. The instructions on the Holts were good and I followed them. You half fill the rad, add the speedflush and then top up with water and run for 10 mins. I must admit to using all the speedflush as I couldn't be bothered keeping half a bottle for the next flush in 2 years! It seemed to work ok. This was my first coolant change & I don't know when it was last done by the previous owner so that's why I used the Holts so I was sure of the service history and method. For a fiver it's worth considering doing.

Again, following the Haynes manual I let the engine cool down a bit inbetween running it. But as it's only run for 10 minutes it cools down quick enough - I just had a cuppa!

The job is easy, but just takes a bit of time. I've still got to dispose of it all. My local recyling centre wouldn't take it so I'm going to ask a local garage what the best solution is.

mep - thanks mate! A brew seems to be my universal timing interval as well!

Thanks Y'all for all the advice.