Unleaded petrol was introduced into South Africa in 1996 as the premium, higher octane grade across the country. There were two main issues to consider when switching to this grade, namely valve seat lubrication and octane quality. At coast, leaded 97 was replaced by unleaded 95, a 2 number drop which necessitated de-tuning in some cases to avoid knock. Also some older engines had soft valve seats which relied on the lead anti-knock package for lubrication. Without this, considerable wear took place showing as valve seat recession.
Any vehicle produced from 1996 onwards would be tolerant to unleaded fuel from a valve seat wear point of view, and should also have been able to tolerate the octane reduction.
I own a 1996 3.5 V6 and run it on either grade without any problem whatsoever as they are the same octane quality at the coast. LRP contains a valve seat lubrication package which would only be necessary on older vehicles having soft valve seats. You will also probably find that the detergent additive package in unleaded is more effective than in LRP, hence a cleaner engine.
"I own a 1996 3.5 V6 and run it on either grade without any problem"… Specific which fuels are you referring too?
“Any vehicle produced from 1996 onwards would be tolerant to unleaded fuel”… and
“LRP contains a valve seat lubrication package which would only be necessary on older vehicles having soft valve seats...detergent additive package in unleaded is more effective than in LRP, hence a cleaner engine."…
Am I correct in making the conclusion that you use UNLEADED 95 as default and LRP from time to time?
“Any vehicle produced from 1996 onwards would be tolerant to unleaded fuel”… and
“LRP contains a valve seat lubrication package which would only be necessary on older vehicles having soft valve seats...detergent additive package in unleaded is more effective than in LRP, hence a cleaner engine."…
Am I correct in making the conclusion that you use UNLEADED 95 as default and LRP from time to time?
Hi Kaas, apologies if not clear. I live in Cape Town where our fuel is unleaded 95 and LRP 95. I use unleaded mainly, and LRP when the station has run out of unleaded. It happens occaionally.
When we moved to unleaded petrol aboout 10 years ago, I switched from leaded to unleaded in my 1995 3.5, and experienced 0 problems. Only the exhaust was no longer burning white - the indication of a healthy engine in the days of leaded petrol.kaas wrote:Am I correct in making the conclusion that you use UNLEADED 95 as default and LRP from time to time?
The question is whether you have a cat converter - if you do, I believe you may damage it with LRP. I don't think the '97 had one installed.
My 2000 (Gen 2) 3.5 runs on unleaded. I do not even consider LRP. Apparently my car has a cat. converter.
Anton
Thx for the respons. I don't think that the '96 3500 is fitted with a cat converter. Although there are still different views it seems to me that the best will be to stick with Unleaded 95 where possible and LRP if needed for my '96 3.5.