More work - coolant, LTT and water pump

So this week I plan on doing my first oil change (thanks to everyone with the help on that thread) and thought while I'm giving her a bit of TLC I'll go a step further and do some additional work. Noticed my coolant level was getting quite low and I've no idea what coolant was last used so plan on doing a flush and re-fill too. As I'm draining the system I guess this is a perfect time to also fit a low temp thermostat but due to the age/mileage should I also consider replacing the water pump? It's a 2002 996 C2 with almost 89k miles. Anything else I should look to consider doing whilst the system is drained? I'll be following the guides on GT4's write up here and also the guides on pelican parts http://911uk.com/viewtopic.php?t=65932 http://www.pelicanparts.com/techart...ATER-Coolant_Flush/29-WATER-Coolant_Flush.htm http://www.pelicanparts.com/techart...TER-Water_Pump_and_Thermostat_Replacement.htm

Yes to both as a good idea, but really you need to find where your coolant's going, too. Check the hoses and if you can pressurise the tank, you may find it has a hairline crack, in which case it needs to be replaced.

Could having the original coolant cap be an explanation for where it's going? Will check for any cracks in the expansion tank or hoses - left it for a week and didn't notice any leaks on the drive.

Does anyone know if the drain plug/washer is the same as the oil drain plug?

Yes it is often the cap. You should see crusty coolant in/near it if it is the problem. If not, look at the bottom of the tank/bulkheads below engine for dried coolant to see if it's the tank. Some of the pipes can perish as well, so follow those out of the tank and check them. Which drain plug are you referring to?

Thanks for your help :thumb: It's the drain plug to drain the coolant from under the engine. Read that the washer should be replaced when the coolant is drained from there? Will have a look around later today and see what I can find. Found one of the radiator fans isn't working either so need to diagnose that problem and potentially replace the fan - looks like this simple coolant flush is turning to a full coolant system replacement

As the cost for this work is starting to mount I'm going to prioritise the work over a couple months. As the water pump is still working should I replace the broken radiator fan (if it needs replacing) over replacing the water pump?

The coolant drain bung is a small 4mm allen key ( might be 5 ) its not fitted anywere else on the car that im aware of and will probably need to be bought from an OPC. The usual problem with a rad fan inop is the resistor thats fitted on the rad houseing , green and white wires go to it from memory .. cant miss it , i think its a ECP part.

Personally, I would leave the water pump for now. My rationale is..... It's working ok at the minute? You have a fan to fix - which for me, something not working is more important than something that is!. A coolant drain rarely gets all the old stuff out so if you need to swap the water pump out at a later date then this will only assist in further flushing the system. Hope this makes sense?

Good to hear you are tackling this properly. I think the cooling system maintenance on the 996 is overlooked and it's possibly the legacy of these cars being from air cooled heritage.

This seems like a perfectly reasonable reason to do the fan over the pump and sort of where my mind was as well. Thanks Harv - whilst its good to be able to spare a few bob doing the work yourself I'm finding it much more rewarding to do the work myself and learn about how the car works. It's making me appreciate it and care for it a lot more than I ever thought I would

:thumbs:

These parts shouldn't cost you a fortune. The resistors to fix the fan units (assuming the motor isn't duff) are reasonably priced (is your car is a 3.4?) I think they can be had for very little expense and members on here have swapped them out for about £15 ea. The LTT doesn't need to break the bank, I sourced mine from Type 911 in Beckenham and you don't actually need to buy a new housing for it though most come with one. The water pump is pricey if you fit an OEM one, the only real difference to note is the impeller is plastic on the original one and the aftermarket ones are brass. Whilst this may not seem like a problem when the bearing of the brass one eventually fails it will machine the crankcase internally if you don't pick it up. Having said that when my pump failed I found 50% of the blades had sheared off which isn't good on an engine who's system is marginal at best. Personally I fitted the cheaper pump and put a note in the service book to change it in 30k or 5 years time. http://www.ebay.co.uk/itm/Brand-new...105411?hash=item2a63b00103:g:VyQAAOSwPc9WwIxE If you disconnect the coolant hose at the pump and raise the front of the car you should be able to drain quite a lot of the old coolant out, if you are messing with the rad then take the front pu off and give the rads a de-leaf anyway and disconnect them to drain the last of the coolant there. Refilling the system use an OAT antifreeze (I use comma red) and mix it strong, like 60% (Max) in favour of concentrate and this will buy you a little more headroom before hotspots around the cylinders boil. Raise the back of the car when filling, and open burp valve, run until thermostat opens and the rads start to warm. Turn off, let it cool for a while and then top up, sometime this takes a few iterations (abit like this post!!) Hope this helps :thumb:

Thanks Harv - I;ve got a 2002 3.6 C2. I'll get the front pu off tomorrow to give it a good clean out as well as fix the fan. I'm guessing one way of testing if its the resistor is to swap the fans over? Picked up the Wahler LTT for £39 yesterday, came with the housing and gasket. Done quite a bit of reading on the water pumps and seems like the advice is to stick to plastic/buy the best if you can. Think I'll leave that alone for the time being in case the fan does need replacing. Will have this on the list to sort out soon though. You've been a great help

Just found a post that answered my question.................... ignore this!