Cold Start Waxstat

[ian2000t]

I've had to leave my cold start lever cable tied in the advance position all winter because I can't find a good waxstat. Well, now I've had enough of trying to find a good S/H one or any other "cheap fix" so I'm going to bite the bullet and pay the £80 odd that Volvo wants and hope it fixes it! I really don't want my car running so advanced for any longer!!

Before I do, does anyone have any other suggestions? I've tried a manual cable but the spring on the pump is so strong I couldn't get it to work.


I have now have 3 waxstat-ends of the cold start device, and 2 spring-ends. I was thinking I had some springs missing, but no, they are both the same.

I have put all 3 waxstat ends in a pan on the hob and let them all sit at ~100C for 15-20 minutes. I would expect to see them 'extend', but the only thing that happened is one of them extended about 2mm. But whereas when it was cold, it was very stiff and couldn't be pushed back in, now it was hot you could easily push it inwards (which would be the cold, advanced position).



I even tried putting the while unit together, leaving the correct gap in the middle for the IP bracket it fixes to on the car, and put a spring on the end, which would pull the cable 'out' - which is what the advance lever is trying to do on the pump. ...but it didn't move AT ALL...



So... am I just very unlucky and have gathered 3 waxstats that are all faulty? Were they that bad a design?

[ngoma]

Originally Posted by ian2000t

So... am I just very unlucky and have gathered 3 waxstats that are all faulty? Were they that bad a design?

Yes they are faulty. The pistons should extend far further than 2mm, and nearly impossible to push back in until cooled to ambient.

Bad design? Probably not a bad use of technology of its day, but one could imagine a better design (better for the overall long-term health of the engine) using the opposite orientation: cold-start lever normally held in non-advanced position when thermostatic actuator has failed, instead of failing to the advanced timing position.

The brass actuator is held in by a collar which unscrews from the housing as you can guess from the threads. Inside the brass actuator is a small reservoir of hydraulic (brake) fluid (or similar) that when heated, actuates the highly-polished piston which slides in the brass bore, sealed by a o-ring. Life expectancy dependent on manufacturing tolerances, and corrosion or damage to the piston which could tear up the bore/seal. Severe overheating could also probably damage it.

It appears to be soldered together, not very user friendly for DIY reconditioning.

Where did you try fastening the manual cable and what type of cable did you use? I have one from a lawnmower that I have set aside to use when the actuator on mine fails.

[ian2000t]

Right, they are definitely faulty then - like I say when they get warm, they don't extend (apart from the one 2mm) but they actually get easier to push in/out.

The only manual cable I had was a bonnet release from a 940 B230FB. I tried to mount it several different ways. I think I finally found some way to mount it successfully, but on trying to activate it, all I did was pull the lever off the end of the cable in the car - that's the point I gave up (and said a few choice words).

I did find this yesterday though:

http://seekpart24.com/bosch/thermost...ent-1467202302

Over half the price of getting one from Volvo, and that's taking into account postage to UK. Sounds bit odd to me, but for that price I'll give it a go...

[ngoma]

Theoretically the CS lever is easier to activate when the IP is rotating, so the key might be to pull the cable while cranking. Anyway, that Bosch P/N looks correct, once you get it installed it should work great! Folks in the US will be curious to see if you get the part in a timely manner; forum member Volvoist mentioned in a recent post that he just recieved the last few available here, both from Volvo and Bosch.

[ian2000t]

Yes, I had heard that it's easier to pull once the engine is rotating. Unfortunately without drilling new holes I could only pass the cable through to the passenger side, so pulling as I turn the key wasn't an option.

Well, I have had an email this morning confirming despatch and I have a tracking number, so fingers crossed! I've had the car for a year now with this thing broken - can't wait to get it fixed!

[petercz]

oh wow at seekparts24 is available ? Great...