1.4mpi changing thermostat and flushing coolant system

[anewman]

First step is to remove the cover from the engine if present. It is held on with 2 10mm nuts, one under the badge, another under another cover. Remove dipstick, pull off cover, take out spare oil cap and place in oil filler. IMO chuck the cover in the bin, it's only there to look pretty.

In this case, as I had some oily deposits in the header tank, I used a coolant flush/radiator cleaner additive. http://www.eurocarpa...m/?NOR2897363 from Euro Car Parts. This seemed to work far better than any other additive I have used at dissolving the gunky oily stuff.

First step is to fully drain the coolant. The coolant drain tap is located at the bottom of the radiator where the hose is. Shown below removed from car in open state. You either need to remove the under tray or fix a hose to the outlet directing it where you want the coolant to end up. To open it you twist and pull out a bit like a bayonet bulb. I, however, prefer to use a different method.

The above is the official method. I prefer to just remove the bottom hose at the engine end and try catch as much coolant as possible in a kitchen bowl. Using this method some is guaranteed to spill onto the road surface, but you will rinse it away when you flush the system. If you leave the coolant cap on the flow will be more controlled.

First remove the hose clip. Press the two tongs together using mole grips. Adjust them such that when they are fully closed the prongs just meet. You can then manoeuvre the hose clip off the end of the hose, and pull the hose off. Be prepared for the flow of coolant. Make sure you do this when the engine is stone cold. Bear in mind that as standard the prongs will be installed to be underneath, but here I have installed it with them on top for easy access.

Spillage

Next step is to remove the temp sender in the thermostat housing. First remove the connector on top. Slide out the horseshoe clip. Then pull out the sender. Note in this case the o ring has been left in the thermostat housing.

To flush the engine block and cabin heater matrix, I insert the hose with the o ring from the temp sender like so below. I put a cloth around in case any stray water cones out.

To flush the radiator, first remove the top hose from the thermostat. Insert the garden hose like so.

To back flush the radiator insert the garden hose into the bottom hose. Direct the top hose downwards ensuring water flow goes away from the engine and in particular any electrical components.

To remove the thermostat first remove the other two hoses

Then with a 13mm socket and an extension bar, remove the two nuts holding it in place. Be careful not to lose the nuts or washers as they will disappear somewhere down the back of the engine. I would suggest removing the nuts fully with the socket so they stay in there, then when removing the thermostat to hold both washers in place.

I was having a problem with the o ring between the thermostat and the cylinder head leaking. It is clear there is some sandy residue here which is likely to be from when I tried using Bars Flush. It seems this may have been the cause of the leak.

I purchased the OE o rings, but decided these were a little small. The OE ones are specced at 30.2mm x 3mm. I fitted a 30mm x 3.5mm o ring, which seemed a better fit to me.

I also cleaned out the header tank. Remove the hoses, pull off the plastic thing at the back holding all the wires and use a deep 10mm socket to remove the 2 double pronged bolt type things. Pull off the hoses attached to the side. The coolant tank then lifts straight out. I used brake cleaner to remove the oily gunk and thoroughly rinsed.

Everything back in place at the thermostat. Tighten the nuts to a torque of 20Nm (from Haynes manual).

Nice and clean again.

Make sure all the hoses are reattached and the clips in place (yep I'm the idiot who once tried filling the system with the bottom hose off). Fill the expansion tank with coolant. I usually top up via the hole vacated by the temp sender too and replace it when coolant has reached the top. Replace the cap, remove all tools from the engine bay etc, run the engine till the fan cuts in then turns off. Let it cool and top up if necessary. Check for any leaks at hoses you have disturbed and at the thermostat.

Edited 15 April, 2012 by anewman

[Joe67]

did you add the cleaner additive to the old coolent before flushing,if so long was it left in the coolent?

[anewman]

I followed the instructions on the bottle I think in all but I actually drove the car to get use out of the petrol, rather than idling. I added it directly to the coolant, although took some out first to ensure coolant would not go above the max mark.

I would certainly recommend the one from Euro Car Parts in the above link, even though the price is quite high. It worked far better than any of the various ones I tried from Halfords. I think there's a discount code for this site somewhere, probably something like BRISK25

[Joe67]

i followed your guide and used the same stuff from euro car parts,though my coolent bottle didnt clean up as well as yours lol.cheers

[anewman]

As stated I removed the bottle and gave it a good clean with brake cleaner. The bottle was new though and I think the plastic does get stained over time.

[t_j]

Many thanks for this guide, its a job coming up that I have to do soon at the coolant is filthy and the thermostat needs changing!! :thumbsup:

[IanWright]

Great instructions!! Thanks.

The only problem I had was in removing the bottom hose clip. It was a bit of a fine setting with my 10" mole grips as when it was wide enough to get round the clip, the closed jaws were only just narrow enough to bring the ends close enough together to free the hose - but with a bit of fiddling I got there.

The problem came when I was putting everything back again. I'd slid the clip up the solid pipe whilst draining the system and changing the thermostat. This is quite a bit narrower than the hose, so when it came to putting it back again the clip was in its "fully relaxed" state and I couldn't get the grips around it at a setting that would then allow me to compress it enough to get it back over the hose. Much cursing followed until I engaged my brain and took the clip completely off. It's then simple enough to open it up with a pipe wrench or similar, fit the mole grips, replace it with the mole grips attached and closed, reattach the hose, slide the clip into place, and release.

Learn from my gormlessness and save 30 minutes of pain bent over the car!!

[anewman]

I think there's probably some sort of official tool actually designed for the purpose of removing those clips.

It seems mole grips differ in how much movement they have at the jaws. One way around this is to use a pair of pliers to turn the knurled knob on the mole grips as they're closed. Worst comes to worse you can just replace them with those worm drive hose clips - but I found they tend to tear through the hoses, so the spring clip ones are definitely best.

[simonp]

thanks for guide.

 

 I did a simple coolant change, using the tap, in the first photo. Now, the tap hose is leaking slowly. I'm not sure if its just when unused or when driving. A while after switching off the engine, the hose begins to drip coolant. I've checked the hose tap is closed and it seems to be.

 

Any ideas?

 

thanks.

 

[sergiut2002]

thank you for the instructions .. really needed this.

[Ilirian Rexho]

Great job. Really appriciated!

[ensher]

Hi Folks, I realise I'm new here and a bit late to the party but I'd really appreciate taking a look at what I assume should be photos (19 in all) posted above by anewman back in 2011/2012 before I tackle a coolant flush on my new-to-me 2002 Skoda Fabia 1.4MPI Classic, as I don't know where anything is on this car yet. BUT all I can see above instead of pix are thumbnails asking me? someone? to update the account on photobucket to 'enable 3rd party hosting'. Any way round that so as to see the images? Or if not are there any better posts elsewhere on the forum with similar helpful pics for a newbie? (My problem is: oil in expansion bottle and a little mayo on the cap; no mayo visible in oil system; low power and slightly lumpy running; but no significant coolant loss and temp seems stable though coolant warning light shows intermittently). Thanks for any useful pointers

[Rooted]

Welcome.

Worth posting your question in the main Fabia section where someone might see and answer a bit quicker.