K Series fluids

[Youds7]

I bought my 7 last July, it's an S3 1998 Supersport with K series 1600 engine, 6 speed box and AP Suretrac LSD. 
I want to do my own servicing but would like confirmation/recommendations for the correct oils and fluids to use. 
The VIN p,ate on the car references oils and fluids but probably things have moved on since 1998!

Coolant - Comma Xtream red. I cannot find this. Is Comma Xtream G30 the same thing? It says in the spec that the colour is violet?
Engine oil, I'm proposing to use Comma motorsport 5w-50.

Gearbox oil! I think I've read that Red Line MTL 75-80 GL4 is recommended for the Caterham 6 speed box?

Diff/LSD - car says EP 90 but I recall reading somewhere that LSD's need a special oil?

Any help would be greatly appreciated. 
 

[Jonathan Kay]

In my 1998 1800 K I use:

Coolant: Comma Xstream G30.
Engine oil: Comma Motorsport Fully Synthetic 5W50 Motor Oil

Jonathan

PS: NB Club discount at Halfords.

[7 wonders of the world]

AP suretrac uses a stock oil, plate LSD's need a friction modifier (extra slippery) to reduce plate chatter at low speed.

Opie also offer a club discount too though you might find MTL cheaper on EBay remember it's sold in US quarts (.946Ltr)

[paul richards]

AP Suretrac uses simple 80-90 gear oil. 

[John Vine]

Agree with #2.

An alternative to Red Line MTL is Comma SX 75w-90 GL4 Semi-synthetic(with Opie discount).

JV

[eric]

1600 K ex race car 

I use 15w50 Motul 300V, a race oil  . Other oils with a  low viscosity , give a too low oil pressure . Dangerous for the engine .

In the 5 speed gearbox I use Red Line Heavy Shockproof  red  , same in the De Dion rear axle  with LSD.

Motul for the coolant and the brake fluid 

[Leics AR Ian Payne]

Strictly speaking the gearbox and diff use different specification oils - one GL4 and the other GL5.

[Roger Ford]

15w50 is a bit thick at the cold end. Fine if you warm your engine properly before starting but if you tend to just jump in and go I'd suggest 5w50 was a safer option. Like others I used to use Comma 5w50 Motorsport in my race K series. Some used to go for 5w40 or 10w40 for lower resistance (and therefore possibly higher power) but it did have a noticeable effect on oil pressure. Though losing the sump plug had a much more drastic effect on oil pressure, and was quite common when you ran the plug over kerbs. Hence many of us had the sump plug relocated to the other side of the sump - and I'd strongly recommend that mod to anyone who runs the kerbs a lot on a K-series.

[7 wonders of the world]

Eric

If the enigne is in good order them 5w/50 is correct for th engine

Red Line heavy Duty shock proof is a GL5 spe coil and MUST NOT be used in conventional syncro gearboxs - it is fine for some sequential and dog boxes though.

Again the OP states AP Suretrack which is an ATB and therefore needs only a conventional gear oil