The watch word unfortunately will remain "BUYER BEWARE" AT ALL LEVELS. And check, check and RE-check!!
I did a lot of research before I got Castrol GTX for two (NEW) cars 1. 1982 Honda Accord 2.1985 Toyota Camry both 4 bangers. CR's at the time highly recommended Castrol GTX. I performed 2/3k OCI's. the Honda Accord was run app 97,000 miles and the Toyota Camry was run app 95,000 miles. Both vehicles' engines were varnished and sludged. The Toyota Camry was more varnished and sludged and the most graphic in that it sprung a leak in the manifold which Toyota declined to cover under any warranty (both goodwill and secret) and burnt valves etc. Just the engine repair costs were app 2500. (on a car sold after more massive repairs for 4500). The engine was almost gross. Part of the repair was to remove the sludge and varnish.
My only AXE to grind is that I would not want varnishing and sludging to happen again to any one of my engines. So the next 8 vehicles I have been using (synthetic) Mobil One 5w30 for app 665,000 miles. I also use 0w20 (11,000 miles and 5w40 (69,000 miles) Any spot or scheduled valve cover removal showed the innards to be spotless. NO VARNISH, NO SLUDGE.
Keep in mind that I do 15,000 mile OCI's with the 5w30 vehicles!!! I do 10,000 mile OCIs with the 0w20 product only because it is still under warranty and will have no qualms going to 15k-20k after. I also do 25,000 mile OCI's with the TDI application
So with only 10 ANECDOTAL data points, I personally would avoid Castrol and specifically GTX. Would anyone dare to run the Castrol product 15,000 mile OCI's?
There is a Castrol that is "tailor made" for my TDI application; "GC or German" Castrol 5w40. I ran it for 5,000 miles as the OEM fill. I changed it at the first recommended OCI. However I did not continue Castrol use; because research has shown Mobil One 5w40 aka Delvac One 5w40 to be:
1. cheaper upfront
2. more available off the shelf
3 longer lasting, thus cheaper long term
4. MUCH more robust oil, better protection
[ November 28, 2005, 02:39 PM: Message edited by: ruking77 ]