Brake fluid and engine oil change
I have a 1990 C4 and I'll attempt the full system. Never having done this sort of thing it's a bit scary but the detailed guides on here are giving me some (potentially unfounded) confidence to attempt it.
Where I live I have found the following:
https://www.ahprofi.cz/sada-pro-rucn...iABEgI5lfD_BwE
https://www.biketeile-service.de/en/...derm6x100.html
Are these the right bits for the task?
I believe I also need some 'flare end' spanners?
What oil should I be using? Hopefully not a contentious topic!
Lastly, what is the recommended engine oil to use (probably a contentious topic) and how much should I get for the job.
I am aware of the various guides on here but felt it worthwhile to ask in case current guidance regarding this has developed since previous guides and recommendations were given.
https://www.motiveproducts.com/colle...t-bleeder-kits
No special tools needed to do the oil change besides a large drain pan (12+ quarts). The drain will change 10.5 quarts out of the 12. You will also need two 22mm crush washers. One for the engine case plug and the other for the plug in the thermostat. As for the best oil? That is a hot topic. I use Mobil 1 Vtwin 20W50 in my cars but I don't drive them in the winter.
Good luck and let us know if you have any questions.
https://www.motiveproducts.com/colle...t-bleeder-kits
No special tools needed to do the oil change besides a large drain pan (12+ quarts). The drain will change 10.5 quarts out of the 12. You will also need two 22mm crush washers. One for the engine case plug and the other for the plug in the thermostat. As for the best oil? That is a hot topic. I use Mobil 1 Vtwin 20W50 in my cars but I don't drive them in the winter.
Good luck and let us know if you have any questions.
I had seen Motive mentioned often on the forum but it does not seem to be available where I am located so I wondered if the one I linked to looked ok. It goes up to 20psi by the look of it but I wasn't sure if it would fit on my oil reservoir.
I think it has been using 15W60 until now (I've not yet had the chance to drive it enough to top it up due to the weather).
I was also interested in what brake fluid is recommended. I've never done this before so I have zero idea about it.
What brake fluid? You want a good quality DOT4. I use ATE Type 200.
https://www.ate-brakes.com/products/brake-fluids/
15W60 should be ok. What level of ZDDP does it have? You want at least 1200 ppm to protect your cam.

Don't worry about any of the process..follow Ricardo's diy on the bleed. And you will be fine.
Oil change...you will kick yourself afterward for ever having paid someone to change your oil...
I like flat-tappet approved Mobil 1 15w50. Readily available at Walmart (they have that in Prague surely).
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Engine oil, a million words typed on this topic! For me with, UK weather, garaged, low winter miles, then I've been using for the last few years Millers CFS 10W50 NT+ Not cheap by any means, but right up there as a favourite with UK and EU classic racers and rallyists (i.e. Tuthill 911 rally/racing builders and race support) - if Millers CFS is good enough for Richard Tuthill and his HERO customer rally 911's then I'm happy too.
Are you intending to also bleed the C4 diff lock slaves?
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Engine oil, a million words typed on this topic! For me with, UK weather, garaged, low winter miles, then I've been using for the last few years Millers CFS 10W50 NT+ Not cheap by any means, but right up there as a favourite with UK and EU classic racers and rallyists (i.e. Tuthill 911 rally/racing builders and race support) - if Millers CFS is good enough for Richard Tuthill and his HERO customer rally 911's then I'm happy too.
Are you intending to also bleed the C4 diff lock slaves?
The speed bleeders look like a good idea and I think I have sourced those.
I was strongly considering trying Millers and I can get that here, although I've only found 10W60 so far but I'm sure I'll be able to find 10W50 if that's a better option (I seem to recall that a lower range was better but I cannot recall if that's a figment of my imagination or if it really matters as much these days. The car will probably be used exclusively on the street although there's a chance that it might see a track.
ATE brake fluid seems a popular choice on the forum.
Finding a 7mm flare spanner seems to be somewhat challenging - is a flare spanner necessary if care is taken?
The 964 and 10W50 was more about helping maintain a thicker viscosity (50) than a more commonly used 40. Classic high mile engine that does get thrashed didn't want to go too thin. Funnily enough, since switching to Millers my temp gauge (with oil cooler fan currently not working) has never peaked more then the 9 o'clock position (except when sprint/hill climbing). Had a good chat with the chaps at Millers to get my needs right.
The 968S I used Miller CFS 10W60 (not sure if it was an NT). The engine does get used hard as it's not until 4.5k+ revs I can feel the variocam do it's stuff. Engine doesn't really perform until I boot it through the gears. Big smiles payoff. The 60 rating has maintained great oil pressure and temps so far. Also put on to it by a well known 944/968 endurance racing preparation and support specialists. Again not cheap. However, next oil change I might check again back with Millers and maybe go the 50 route.
Bottom line being I guess, never skimp on a good quality oil. Peace of mind it will cope with all sorts of mad behaviour

The 964 and 10W50 was more about helping maintain a thicker viscosity (50) than a more commonly used 40. Classic high mile engine that does get thrashed didn't want to go too thin. Funnily enough, since switching to Millers my temp gauge (with oil cooler fan currently not working) has never peaked more then the 9 o'clock position (except when sprint/hill climbing). Had a good chat with the chaps at Millers to get my needs right.
The 968S I used Miller CFS 10W60 (not sure if it was an NT). The engine does get used hard as it's not until 4.5k+ revs I can feel the variocam do it's stuff. Engine doesn't really perform until I boot it through the gears. Big smiles payoff. The 60 rating has maintained great oil pressure and temps so far. Also put on to it by a well known 944/968 endurance racing preparation and support specialists. Again not cheap. However, next oil change I might check again back with Millers and maybe go the 50 route.
Bottom line being I guess, never skimp on a good quality oil. Peace of mind it will cope with all sorts of mad behaviour






