I used STP once, to pass emissions. It was an engine with high HC, going through oil faster than fuel. I needed to pass emissions, drive for another month to find my next car. It did the job. But this is also in 100’ CA heat. The engine was already making bearing noise, so wasn’t worried about any more harm.
Back in the day we called that kind of stuff “motor honey”.
I had a friend who put many different brands (whatever was cheapest) in his 1976 Ford Granada (nicknamed “Grenade”) that smoked like George Burns.
A dose only lasted a few hundred miles.
Search “Lucas Prince of Darkness”. Then wonder if the company with that name that could not make reliable auto electrics could also make effective oil additives. If it is not the same company, one could wonder what people were thinking when they used that brand name.
I passed a Lucas factory in the hills of east Tennessee. Jethro Bodine may be the head of R&D there. Of course he did graduate 6th grade.
Years ago I remember throwing a few cans of STP in engines which were on their last legs. It was common to do that at the gas stations I worked at. It did help to reduce the smoking. It didn’t help in cold weather starts.
Even though I haven’t used STP-like “motor honey” in years, it may still be a useful band-aid to consider to baby a worn out engine a little longer. Though I’m not sure how the oil-driven VVT mechanisms enjoy oil that thick.
From Chrysler’s TSB#09-003-01 on oil additives:
Engine oil additives/supplements (EOS) should not be used to enhance engine
oil performance. Engine oil additives/supplements should not be used to extend
engine oil change intervals. No additive is known to be safe for engine durability
and can degrade emission components. Additives can contain undesirable
materials that harm the long term durability of engines by:
• Doubling the level of Phosphorus in the engine oil. The ILSAC (International Lubricant
Standard Approval Committee) GF-2 and GF-3 standards require that engine oil contain
no more than 0.10% Phosphorus to protect the vehicles emissions performance.
Addition of engine oil additives/supplements can poison, from the added sulfur and
phosphorus, catalysts and hinder efforts to guarantee our emissions performance
to 80,000 miles and new requirements of 150,000 miles.
• Altering the viscosity characteristics of the engine oil so that it no longer meets
the requirements of the specified viscosity grade.
• Creating potential for an undesirable additive compatibility interaction in the engine
crankcase. Generally it is not desirable to mix additive packages from different
suppliers in the crankcase; there have been reports of low temperature engine failures
caused by additive package incompatibility with such mixtures.
Ten years ago when I worked at a Dodge dealer the service manager was receiving kickbacks from the BG chemical salesman. Every service included a BG additive. When I performed an oil change or other services I would pour the additives into the oil drain. There are several bulletins against the use of additives as well as warnings in the owners manual. I would estimate that one third of my former coworkers (including the mentioned manager) are fuctionally illiterate.
Different ‘Lucas’, not the English electrical equipment company. At least the English company made parts that (temporarily) made cars work.
“Studebaker bought STP in '61, so I bet STP stickers were pretty common on Studes from that point on…”
A little bit of trivia:
STP originally stood for Studebaker Test Products.
After Studebaker’s demise, the succeeding owners of this line of additives said that it stood for Scientifically Tested Products.
It is interesting to note that neither owner ever labeled this product as being “tested and approved”.
Submitting a product for testing is one thing.
Passing that test is another issue entirely.
Kind of like ‘patent pending’…
STP and winter driving don’t mix. The oil is so thick that during the winter it’s almost a solid.
Good way to kill a import,Boss used to use 10W-40 in his wifes Honda and couldnt seem to understand why it didnt do exactly right,now everything gets 15W-40 Mobil(since the money crunch)Our Chevy trucks last 300K without additives-Kevin
now everything gets 15W-40 Mobil(since the money crunch)Our Chevy trucks last 300K without additives
15w-40 in NH won’t fly. 15w oil is too thick for -10 degrees.
I’ve been using nothing but 5W-30 for the past 20+ years and have no problem keeping vehicles well past 300k miles.
It really wont fly around here either in the winter months,our new mechanic (who is an experienced logger) is stressing the importance of proper viscosity oil-the boss no longer has the Honda after belly aching about it-the heavy oil belongs in the old cats and wore out vehicles(there is 10W-30 diesel oil availible now,we have used straight 10W in the oldest Macks before(no longer in service)I always use what the manu recommends ,no problem with engine life either,the old heavy oil sure creates a lot of drag on cold starts-Kevin
Whew didnt have to work today,too much rain/ anybody ever try K-Guard gutter sheild? My bad on the oil-the mechanic had switched the pickups to 5W-30 Mobil(from 10W-40 Pennzoil) and we havent had any longetivity issues,right after He took over the maintenence-Kevin
The absolute worst use of STP I ever saw was a college music student whose old French horn had leaking rotary valves. He reasoned that a few drops of STP dripped into the valves after removing the tuning slides might help this problem. What it did was render the horn unplayable. It took the local music shop quite a bit of time to disassemble the valves and clean out the STP. The horn eventually had to have the valves relapped–quite an expensive repair that the student was trying to avoid.
There are a lot of ways for students to learn. This is one I hadn’t heard of before. I’m sure it’s a lesson that’ll stay with the young fella.