Coolant and Heating System overhaul 3

Introduction

(article penned by CovKid)

Firstly, although you could in theory just change the thermostat if its playing up, its better to do both if the condition of them is unknown. Likewise, if the pump bearings have gone requiring a pump swap, you should change the thermostat too. In general, this job can only be seen as an overhaul as there is so much work involved, it makes little sense not to fit new. The 1.9 differs from the 2.1 which has a different thermostat housing. If I had to give this job a grade in terms of difficulty, I'd give it a 10 out of 10 for testing patience and requiring tools most peoiple won't have to hand to remove stubborb bolts - be prepared for that!

Diagnosing Pump Wear=

Sudden loss of water pressure, extreme needle movement on temperature guage (ie Max) and clouds of steam may be a first sign. When cool, jiggling the water pump pulley (to left of main pulley) will cause a dribbling or gush of water on the ground. The pulley will probably feel loose if the bearings have gone.

Heres my comparison between a new and worn water pump: https://www.youtube.com/watch?v=LghNy400HzI

Removal Process

1. Expect stuck thermostat bolts (or just one stuck one) which may even require the use of a milling machine to drill out any that won't budge. The thermostat housing is (I believe) obsolete so treat it like its made of gold. You may need to partially grind away parts of old pump in order to remove thermostat housing from pump - then deal with bolts.

2. The thermostat will likely be corroded in and need a screwdriver or small cold chisel to get it out. Clean all casting faces very carefully, removing deposits and any old gaskets before fitting new thermostat.

2. Expect VERY VERY tight allen bolts on lower metal water pipes which could leave the heads chewed. Plus-gas helps but not much! A rounded bolt head remover comes in very handy and no matter how much the set is, it'll be cheaper and easier than faffing around with chisels or easy-outs.

3. You'll need instant gasket, using a thin smear at major joints for a watertight fit.

4. You'll need to remove both water pump pulley and main pulley. Main pulley will be in the way of all the stuff you need to get at. Pulley bolt will shift with a big adjustable, locking the fanbelt, and smacking the adjustable sharply with a lump hammer to free nut. Water pump pulley bolts can be loosened at same time as main pulley bolt, but only loosen all these bolts first - then remove the pulleys. The belt needs to be attached to do it.

5. You're highly unlikely to complete the job in one day - sorry....

6. You slide thermostat and pump (as one unit) on to the two metal pipes, leaving one pipe loosely bolted to give you enough room to do this. Its annoying, but it will go once you have pump lines up with its three studs. Use plenty of instant gasket around pipe that has the small O-ring - you do not want to chance leaks there. That O-ring has a habit of staying out so check carefully that it DID go in with pipe and its not hanging out somewhere. Instant gasket will help it slide in and help seal it properly.

7. You'll need to fill and bleed the system with plain water to make sure it doesn't actually leak, before draining and refilling with the 50/50 antifreeze mix.

8. Do not push yourself and don't attempt this job in the hope you'll be at some camper meet the next day. You will be disappointed.

9. Just pay someone else to do it - its a horrible, nasty, contemptuous job and there will be plenty of moments when you'll contemplate removing the engine in desperation or even suicide. Its not nice.