change to thicker oil, now engine sputters

[harimon21]

hi tsikoteers,
i changed oil yesterday. For the past 3 consecutive oil changes i have been using castrol magnatech 10w-40 semisynthetic. Before that i was using castrol 20W-50. Switching from 20-50W to 10W-50 semi-synthetic was no problem. But yesterday, i decided to change my oil back to thicker castrol 20W-50. Because the car is old (singkit '91-EFI), thinking that might help reduce the smoke every cold starts. Having changed to thicker oil, immediately the engine starts to behave weird. The engine was shaky, sputters, and idle was very erratic. Parang sakal ang takbo ang I cannot go full throttle without the engine getting wild, sometimes dying. I can only drive 1st to 2nd gear. Seems to me that the engine was severely in a bad timing. But the timing was never adjusted whatsoever during the change oil.
What could have caused this? The thick oil? Perhaps the slight overfill of oil? Please help!!

[ghosthunter]

I would hazzard a guess that the oil overfill might have something to do with your problem.

[voltscastillo]

it could be something totally unrelated to the oil... baka may nahugot na vacuum hose somewhere nung kinakatikot ng mechanic. maybe napundi na yung isang spark plug.

engine that old... shouldnt matter what oil you put in. but the only reason i see now for going back to 20w-50 (apart from the cost) is to temporarily stop leaks (shell yellow had a somewhat noticeable effect on my old LXi's leaky rocker gasket...nabawasan talaga).

[harimon21]

it definitely has something to do with the change. I checked the vacuum hoses and everything is fine.Will an oil overfill cause such symptoms? Because I checked the oil level and it is beyond the MAX mark

[blacksun25]

ilang liters ba ng oil ang nilagay ng mekaniko? check mo yung distributor mo kung may oil leak. baka nasira yung mga oil seal dahil sa dami ng langis na ikinarga. it's just a guess. pwede rin na coincidence lang talaga yung paglabas ng mga symptoms na sinabi mo right after changing the oil.

possible din na bad fuel ang dahilan. pa-check mo na lang sa trusted mechanic. hth.

[speed unlimited]

I think there nothing to do with the change in viscosity of oil . If it overfill the cause will be to much smoke on your exhaust when you rev. the engine. It might be a coincidence try to check your sparkplug there must be a misfouled. Check all the possible cause like spark plug wire set, distributor cap, rotor , Double check your timing. Hope this help . Let us know what happen when its already okay.

[gremz]

any update on this?

Same situation here, car is toyota corolla 4afe, automatic, 94' change oil from magnatec 10w40 to petron ultron minerel 20w40. Then got a full tank of shell unleaded E10(first time, used to load caltex silver not e10) on the same day. Then after 2 days, BANG! Parang palyado makina. Mechanic can't find any reason why the engine should behave like that, checked all the hoses, changed spark plug, changed High Tension wires, pero ganun pa rin, intermitent na medyo madalas nginig ng makina then hirap humatak. Atf is good, bago lang.

Next gas refill, balik ako sa Caltex Silver, walang E10, medyo di naging madalas ang nginig, then shift to Caltex GOLD naging pino ang idling, pero minsan na lang ang nginig.

Just wondering ano pa kaya ang pwedeng dahilan. Aircon VCV is ok, bagong palit lang sa Toyota North. Idling at 950~1000rpm cold start, then 850 when hot with or without A/C.

Kakatakot kasi pag nanginig parang mamatay hehehe.



Tks sa magrereply.

[harimon21]

thanks for the replies. Had some oil drained to proper level, but symptoms still there. It really had nothing to do with the oil, I suppose. Instead I checked the sparkplugs and found 1 bad. Had all 4 replaced na also the wires, then I cleaned the distributor cap and the contact points in the MAF sensor. Idle seems to be more stable plus nawala rin yung pagbaba ng rpm pag nag-oon ang aux fan. So far so good. Hope it stays this way