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Is It Ok To Use 5W30 Regular Oil In A 1990 350 Tbi?

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blackandgold51

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I made a mistake a put in tje wrong oil the other day. 5w30 regular oil which i usually use 10w40 regular oil.

I out a new filter on too.

I stay in new orleans and it does get cold so im wondering if it will be okay with a 5w30 oil until next oil change
 
It wont hurt anything,provided the engine doesn't smoke or have loose bearings,has good oil pressure..if you were going to tow in 80+ degree heat I would prefer higher viscosity,especially if it has high miles on it..

It has been proven a light viscosity oil actually lubes better and will flow faster to bearings and all other parts after a cold start.."the most engine wear occours in the first few minutes after a cold start" is more than a just sales pitch,its true..in cold weather thinner oil also helps quick starts,the engine wont be dragging due to cold thick oil,cranking speed will be faster..
 
mrk5 said:
I think 5w30 is the factory recommended oil. I would think you'll be fine.
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Black and Gold, you will be fine. I am two hours east from you on the Gulf Coast with probably around 200k miles on my '91 TBI 350 and still run the factory recommended 5w30 (mind you, synthetic these days - Amsoil).
 
big-blue said:
Black and Gold, you will be fine. I am two hours east from you on the Gulf Coast with probably around 200k miles on my '91 TBI 350 and still run the factory recommended 5w30 (mind you, synthetic these days - Amsoil).
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I thought tbi 350s from a different era dont use synthetic oil.
 
blackandgold51 said:
I thought tbi 350s from a different era dont use synthetic oil.
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Not sure if I understand your statement. You can fill with 5w30 synthetic if you so choose. Lots of different brands that meets and exceeds the original specifications. Lots of benefits to doing so as well.
 
Viscosity factors aside, most oils have a percentage of synthetic oil in the mix anyway; some more than others.

I'm still stuck with a non-roller engine and oil is somewhat of a problem since the slicker additives have been found to ruin the newer catalytic converters and the Feds stepped in with Ecologically Good Oiks.

Then there's Valvolene's "Next Gen" products that make use of recycled drain oils and re-produces oil with all the additives replenished. Sounds good, right?
 
Joe In Montana said:
Viscosity factors aside, most oils have a percentage of synthetic oil in the mix anyway; some more than others.

I'm still stuck with a non-roller engine and oil is somewhat of a problem since the slicker additives have been found to ruin the newer catalytic converters and the Feds stepped in with Ecologically Good Oiks.

Then there's Valvolene's "Next Gen" products that make use of recycled drain oils and re-produces oil with all the additives replenished. Sounds good, right?
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So regular convention oils have a mix of blend synthetic amd full synthentics?
 
Joe In Montana said:
Viscosity factors aside, most oils have a percentage of synthetic oil in the mix anyway; some more than others.

I'm still stuck with a non-roller engine and oil is somewhat of a problem since the slicker additives have been found to ruin the newer catalytic converters and the Feds stepped in with Ecologically Good Oiks.

Then there's Valvolene's "Next Gen" products that make use of recycled drain oils and re-produces oil with all the additives replenished. Sounds good, right?
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I throw in a bottle of zddp additive with every oil change on my flat tappet engine. Some say you don't need it after the break-in but I figure it's cheap insurance.
 
paratrooper307 said:
I throw in a bottle of zddp additive with every oil change on my flat tappet engine. Some say you don't need it after the break-in but I figure it's cheap insurance.
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I do too. I use Lucas Break In Lube for new engines. The ZDDP is important for not just film strength but also as a shock absorber for the tiny line-point of contact between the lifter and the cam.

It's the ZDDP that's been removed to protect the catalytic converters from contamination and early death.

There are some people who don't understand the cam manufacturing process and assume that cams are hardened, when in reality cast iron cannot be hardned.

Parkerizing is however done to the cam lobes to create tiny fissures and microscopic canyons and craters that capture and hold oil to minimize metal-to-metal contact until a safe wear pattern can be established between the cam and the lifter face.

For the most part, roller lifters are exempt from needing this Parkerized surface



Sidebar: the most frequent lobe failure on a non-roller cam 350/5.7 GM, is to which cylinder and which valve?

10 points for the first person with the correct answer and the reason why their answer was given.

.
 
Every small block I've had that ate cam lobes (mostly 307's and 305's) and others at garages I saw,had the #1 exhaust valve lobe flatten first--this made the exhaust back up in the cylinder and try escaping back through the carb at higher rpms...

I've read too much ZDDP is not good either..

I have seen new cams installed and properly broken in with the additive and right oil,still flatten a lobe in less than 2000 miles,I guess they don't make 'em like they used too...
 
I could have sworn I read somewhere, during the oil and filter research, that synthetic oil isn't really what a lot of people think it is, thinking it is a fully man made lubricant. What I seem to remember is that synthetic oil is an ultra refined conventional oil, with extra additives, we've come up with and blended in with that ultra refined oil, to give it a new property to better handle heat and break down.

Regardless, Im gonna go ahead and freak you all out and say I buy the 5qt jugs and another single at WalMart of the Mobile 1 full synthetic 15/50 oil and run a Mobile 1 filter as well. I've had no problems with maintaining oil pressure, I started using it to aide in seemingly noisy, cold morning lifters. I've even tried other weights that do not help. If you really look at the thickness of the oil in synthetic makeup, it's already pretty thin, yes it may be a touch thick during cold starts for some peoples liking, but oil pressure is up and constant right after start, let it warm up a bit and shes really good to go. Mainly used it as someone else mentioned during times when I was pulling trailers around and just recently when I towed a 5500lb trailer back from Indiana to Washington, just kept it in there until next oil change and with winter coming, it'll probably drop to a 10/40 weight. We really don't get down below freezing here for anything thinner.

By the way, this is in the '05 Avalanche with the 5.3 engine.

As for my other ride, the Burb with the 5.7 TBI, I ran nothing BUT 20/50 when living in Phoenix,Arizona due to the extreme heat and high mileage of the engine, had well over 250k miles, so it would burn a little and leak past the seals real easy if I used anything lighter. Also it was quieter running that thicker oil. Now I did run that engine up to a cold weather climate one year with that same oil still in it and I'll tell ya, it didn't like it. It was slow cranking, so I did end up going with a thinner oil then.

But once I switched it over to full synthetic, it was running 10/40 normally, ran good and sounded even better. Some may think I'm nuts, but I feel I actually heard a difference in engine type noises when I switched from conventional to synthetic.

If I were in a more cold climate that regularly sees temperatures in the teens or lower, I'd most likely run a 5/xx flavor though.
 
No your not nuts...I've heard engines that had clattery lifters go silent a few minutes after a synthetic oil change...

When I was putting used crankcase oil in my 6.2 to keep it full when it leaked a quart real fast till I could do something about it,I swear it ran smoother and quieter,the oil I was getting from a friends shop was a mixture of regular & synthetic drained from cars that were owned by well off people like BMW's and Mercedes,that insisted on synthetic only,every 3000 miles,and it still looked nice and clear..and some was 5W-20 ,some was 5W-30 and some of it was 10W-30 ,most likely..

I know that wasn't the best thing for it,but a full crankcase of "any" oil is better than letting it run low or empty!..
Hasn't seemed to bother it any so far,but since I put 15W-40 diesel oil back in it,it sounds more clattery...and I also noticed the used oil stayed clean on the dipstick,while the diesel rated oil turned black as coal in the first hour..guess the extra detergent does work..

I used to run only Castrol 20W-50 in most of my vehicles back in the 80's,with no apparent issues,never had one have an oil related failure--when the temps dropped below 20 above in the winter though,the starter did drag some,and you'd hear the lifters "pump up"--thats when I'd switch to 10W-30..after I was forced to stop working and money was real tight I started using "cheap" Walmart "Tech 2000" brand oil,never had any issues with it either..

I had a few engines that were fussy about brands--I ran Amalie 20W-50 in my '72 K5 once when the store I worked at was out of Castrol--right away I noticed the oil pressure dropped from 30 psi at idle hot,to 10 to 15,and I'd normally get 45-50 psi at highway speeds,it never went over 40 psi...

When another customer mentioned he noticed the same thing happening in his vette,he demanded 5 quarts of another brand,he too liked Castrol--only other brand we had was Valvoline,he put that in his car and the pressure returned to normal,as did my K5,after the next oil change when we got more Castrol in stock..
I don't know if that batch of Amalie was labeled wrong or what,but it seemed to lose viscosity after the engine warmed up..

I've read 10W-40 isn't a good oil for many engines--something about it having the most amount of viscosity modifiers and additives,and it can gel up or leave deposits..many small engine manufacturers say to avoid it also..
 
Unless one of our gurus has anything to say otherwise about internal clearances changing, GM went to 5W30 on the later SBC's (page 6-16 here shows it https://assets.gm.com/manuals/chevrolet/1998_chevrolet_1500_owners.pdf ) I don't know why it would make any difference to the negative.

Note that GM thought 10W30 was ok as long as it didn't get below 0*.

My car recommends 5W20 as I recall, but the "ok" list includes 5W30 and 10W30. FWIW, I've not noticed an economy difference between any of them.
 
I went to a petroleum seminar about 10 years ago and I was told the reason why GM went to the lower numbered viscosity oils was that they went from high pressure lubrication - to metered oil flow for the tighter clearances and dimensions of their modern more fuel efficient engines.

Mebbee!?!?
 
diesel4me said:
I've read too much ZDDP is not good either..

Nascar engines run super thin oil. The ZDDP is only required if you have a flat tappet cam. The guy that built my 383 and builds 434 SBC motors told me to put in a bottle of ZDDP every oil change. I run rotella T diesel oil with a bottle of ZDDP.
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And we've run 10-30 in Iowa all my life and it gets below zero for months sometimes in the winter.
 
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