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Synthetic = faster oil leak?

I

ILMODC

New member
Hello,

Been using Synthetic in my wifes 1998 GTP for some time now. It's pushing 250K Miles on the motor. I picked up a 2000 GT last year and just now switched to Synthetic. The GT has 150K. Car has a small drop of oil but now since the oil change has gotten really bad. I just haven't had a chance to get under the car to investigate. What was maybe a 3rd of a quart between oil changes has turned into about a quart if not more.

Would the swap to synthetic worsen already bad gaskets and leak more/faster?

This weekend I'm hoping to get under there and take a look. I'll check the oil sensor near the filter first for any obvious leakage. No matter the source of the leak, the puddle left is dead center under the engine.
 


sounds like the oil pan or the rear cover or its crank seal is leaking.

Synthetic oils have been known to make a oil leak worse, or start leaking in older engines.

my pan and rear cover were leaking, i had a wet with oil and sweaty looking pan and a drip on most pan bolts. i used to leave 3 nice drips under the car everywhere i parked lol
 
the oil pressure sender could also have failed, they make messes when they break, and they are plastic. I have had at least one fail in the last year.
 
thats a pass side leak. dead center is a oil pan or maybe a valve cover leak trailing to the oil pan.

ive had, and fixed all the above leaks. aka all new gaskets, engine pulled out. no more leaks :rolleyes: knocking on wood before i jinx myself lol
 
Synthectic oils normally have more cleaners and will break down build up faster, so it's possible that it's clearing away build up around the gasket area and making the leak worse now.
 


I would not think it would make that much of a difference. it is supposed to be the same viscosity. It just resists higher temperatures and breakdown better than conventional.


*Walmart has 5 quart jug of Mobil One Full synthetic high mileage 5w30 for $23 right now.
 
Thicker viscosity yes, but it is the cleaning agents that do the damage.

I got 2 5l jugs of the Valvoline Synthetic in a trade I did. Works out that I paid $10 per jug. I used one on the car, but noticed more oil leaks.
 
Good feedback gang, thanks! Giving me someplace to start.

Hmm. Should I go thicker? I think I'm running 5W/30. I'm in So Cal and its a daily. What's a good viscosity? I'll get under there and check the oil pan bolts and parameter. Is the gasket a PITA?? I'll check that oil sensor too.

If all checks out, should I got back to dino oil?? Don't have any cash money to be putting into the motor...
 
Check and fix any leaks. The pan gasket isn't that hard if that's the issue. In the meantime you can use an off brand high mileage oil which all are synthetic blend. Maybe some sort of stop leak. Lucas is my favorite but there are plenty of other options. I would stick to 5w30 though.
 
You could run a thicker regular oil, but I wouldn't go thicker in synthetic. 5w30 or 10w30 is just fine for these cars.
 


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