'07 Chevy Tahoe Z71 oil application

[Falcon_LS]

Took a friend to the Chevrolet dealer yesterday for his 35,000 km (20,000 mile) service interval. Up until 30,000 km (17,000 miles), he always had oil changes done at the 10,000 km (6,250 miles) mark. At his last service, he was told to follow a 5,000 km (3,000 mile) OCI, which is fine.

However, we took the vehicle into the service centre yesterday and I know the 10,000 km oil was a 5W-40 synthetic (BP Visco 5000 series, API SL/CF). Now they've switched the vehicle to a semi-synthetic 20W-50 (BP Visco 3000 - the Visco 2000 series is API SJ/CF rated, I'm not sure whether 3000 is SJ or SL). When I inquired as to why they switched it to such a thick oil, the 'advisor' turns around and tells me the weather is too 'hot' and 5W-40 is only meant for the Caprice and Lumina (Australian Holden Caprice and Commodore).

I realise climate plays an important role in oil, but for a new engine with this mileage, I believe 20W-50 to be very thick. The oil cap specifies 5w30, so I 5W-40 would be fine to a certain extent...but 50 hot CST is too thick IMO. I was trying to persuade him to take it to the GMC dealer, where they exclusively use ACDelco 10W-30, which is an API SM rated oil, but he said since it's under warranty, he'll take it to the dealer he purchased it from. Then again, I was pretty sad that they charged him $100 to change the oil and filter, and replace the air filter as per my recommendation. They said the air filter could be blown with air and reused, but it's been there for 20,000 km (12,500 miles) and we're experiencing a lot of dusty weather lately.

Would this truck be alright with 20W-50, or should he switch back to 5W-40 synthetic? These are the only two choices available at this dealer, and he is reluctant to take it elsewhere. Thank you.

 

[GMBoy]

I agree with you're feelings that a 20W/50 is too thick. I think with your hot climate the 5W/40 is a decent choice especially being a synthetic oil. The tolerences inside today's engines are much tighter than before and thicker oils are no longer needed to offer maximum protection.

I agree with wanting to change the air filter too rather than blow it out. Blowing it out probably hurt the filter and it may now have holes letting the dust enter the engine.

And thank your friend for buying one of my products. We build on average 50 trucks a day going over to your country. I could never understand one thing - they never get tinted glass and it's so hot over there.

 

[Falcon_LS]

Thank you for the response, and my friend says "You're welcome!"

Good to see a reply from someone who actually builds these trucks!

As far as tinted glass is concerned, it is illegal in most Gulf countries to have your front windows tinted (except the Emirate of Dubai). You are, however, allowed to tint your second and third row windows on an SUV. I reckon the importer/dealers therefore order vehicles without tinted glass. My personal feeling on this is that it's ludicrous...tinted windows help keep the interior cool on a hot summer's day and improve the AC unit's efficiency significantly. Then again, people pay crazy money for V-Kool, etc.

 

[Falcon_LS]

Figured it would be worthwhile posting here, instead of starting a new thread. The said BP Visco 3000 meets an API SL specification. I believe the recommended oil should meet an API SM and ILSAC GF-4 specification. Obviously the dealer is using this oil, and will have to honour any warranty issues, should they come up. Howver, is there any harm in using a lower API spec oil, without an ILSAC specification?