do i dare put 5-30 snythetic blend in a truck with 200,000 miles on motor? or will it start leaking thru its gaskets

5

Asked by Apr 04, 2012 at 12:04 AM about the 1995 GMC Sierra 1500 K1500 SL 4WD Extended Cab SB

Question type: Maintenance & Repair

1995 gmc sierra z71 5.7 right now no leaks. i want to keep this truck for a long time,please help

6 Answers

345

it's never too late to run synthetic, and why stop at blend? go full syn. pure myth that it will leak. Amsoil Mobil1 Pennzoil Ultra All top synthetic oils

1 of 1 people found this helpful.
1,265

my 95 sierra 5.7 gets 5w-30 castrol high mileage. it's running strong over 270k. it's a partial synthetic blend. definitely a must for a high mileage engine

1 of 1 people found this helpful.
765

stick with the high milage, it has additive in it to recondition seals and prevent/slow/stop small leaks. high milage is not a synthetic of any type. its a conventials still meeting/exceeding all manufacture spec. it just has a slightly diff additive package. few more rust inhibitor, conditioners and cleaners.

1,265

Chris is right, high mileage is the way to go. But castrol high mileage is a part synthetic oil.

410

Sythetic oils are very good. They have better shear stregth which is good when bearing pressures are high (like desert racing with high perf motors) and they excell in severe cold too (better flow) If you're like 99.9% of the people out there and use the engine for normal daily driving, it really doesn't "add" anything to the picture. Its like burning premium fuel in an engine that's not designed for it - it makes you feel better but achieves nothing. Yes, its great oil but unesessary in most circumstances. Its much more important to change it regularly. And oh ya, it has nothing to do with leaking - in fact, if you don't have any leaks as you say, I would even stay away from "high mileage" oil as it contains chemicals that actually attack the seals swelling them in the process and slowing small leaks. In the long run, it degrades them. I have 230,000 on the same engine you describe and have never used synthetic or any additives. Just regular oil/filter changes.

3 of 3 people found this helpful.

I used castrol high mileage for a long time. You can't go wrong with it. But I now swear by Royal Purple. I have a 91 Sierra 350 with 210 thousand and since going to purple my mileage has gotten so much better it's insane. I even talked my dad into using it and he was a dihard castrol guy. He's been using it in his 02 2500 HD and his improved gas mileage blew his mind. It costs alittle more but it's so worth it. Hell I've told friends to try it and if they didn't see improvement I'd pay for the next change. I haven't paid yet.

Your Answer

Add photo

Related Questions

  • TAPPING SOUND WHEN STARTING AND USES ALOT OF ANTI FREZE 7 answers

    I HAVE THIS TRUCK FOR 30 DAYS NOW AND IT HAS USED 2 GAL OF ANTIFREZE. CANNOT FIND LEAK OR ANY EVIDENCE OF LEAKING, HEATER CORE ETC. ALSO HAS A VERY LOUD TAPPING SOUND WHEN STARTED, BUR WILL GO AWAY AF...

    2004 GMC Sierra 1500 4 Dr SLE 4WD Extended Cab LB

    -

    Maintenance & Repair

  • started stalling and dying when in gear 90 answers

    350 motor 4L60E trans Motor wants to stall while in gear (but doesn't do it out of gear once over 1000 rpm it dosent) seem to stall and it is only from a dead stop. Fuel filter has been replaced an...

    1994 GMC Sierra 1500 C1500 SLE Extended Cab SB

    -

    Maintenance & Repair

  • Knocking noise in engine 5.3 GMC 2013 2 answers

    My truck only has 20,000 miles on it and started knocking at 19,000 miles took it to the dealer and they stated it was normal characteristics of the motor. i was a mechanic back in the 70 s and rebu...

    2013 GMC Sierra 1500 SLE Ext. Cab

    -

    Maintenance & Repair

  • Stalling out and wont stay running. Acts like it wants to run but gets choked out. 50 answers

    I have a similiar problem as devin, my 95 Sierra 4x4 it has a 350 5.7L engine and the fuel filter has been replaced I cleaned the injectors out and put a new gasket on. The shop said I have good fuel ...

    1995 GMC Sierra 1500

    -

    Maintenance & Repair

  • Oil pump or something else please help urgent 19 answers

    I have a 2007 gmc 2500 hd with 6.0 gas engine.oil pressure gage dropped to nothing and alarm went off saying low oil pressure shut off engine.oil is clean and up to par.no leaks or knocking pingin...

    2007 GMC Sierra 2500HD 4 Dr Work Truck Crew Cab 4WD

    -

    Maintenance & Repair

Sierra 1500

Looking for a Used Sierra 1500 in your area?

CarGurus has 68,199 nationwide Sierra 1500 listings starting at $2,484.

ZIP:

Search GMC Sierra 1500 Questions

GMC Sierra 1500 Experts

#1 dragonflyoffshore
dragonflyoffshore
Reputation 5,010
#2 John Saffrahn
John Saffrahn
Reputation 3,540
#3 Glenn Clingenpeel
Glenn Clingenpeel
Reputation 3,150
View All

Related Models For Sale

Used Ford F-150
2,194 Great Deals out of 206,316 listings starting at $1,499
Used Dodge Ram 1500
455 Great Deals out of 11,152 listings starting at $700
Used Toyota Tacoma
539 Great Deals out of 40,814 listings starting at $2,495
Used GMC Yukon
376 Great Deals out of 18,226 listings starting at $2,950
Used Chevrolet Tahoe
547 Great Deals out of 29,234 listings starting at $1,699
Used Chevrolet Camaro
226 Great Deals out of 30,943 listings starting at $1,217

Used Cars For Sale

2017 GMC Sierra 1500 For Sale
42 Great Deals out of 44,111 listings starting at $20,121
2016 GMC Sierra 1500 For Sale
78 Great Deals out of 3,645 listings starting at $17,888
2015 GMC Sierra 1500 For Sale
102 Great Deals out of 3,926 listings starting at $15,400
2014 GMC Sierra 1500 For Sale
117 Great Deals out of 4,152 listings starting at $14,495
2013 GMC Sierra 1500 For Sale
65 Great Deals out of 2,009 listings starting at $9,600

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.