Skip the auto shop - Our mechanics make house calls

Q: Will adding Transmission Fluid with Stop Leak to a transmission with over 230,000 miles hurt it?

asked by on

Will adding Transmission Fluid with Stop Leak to a transmission with over 230,000 miles hurt it? Will adding Radiator Stop Leak do damage if I am not sure where the water is leaking from?

A: Both of these additives are designed to blo...

Both of these additives are designed to block small leaks or seepage from a gasket or rubber seal an not to fix major leaks or leaks where there will be excessive pressures, such as coolant leaks into the combustion chamber of the cooling system or leaks in high pressure areas of the transmission.

I would not recommend the use of these products unless a manufacturer specified to use them, like how GM did on their earlier models of the modular motors that had coolant leaking through the pores of the engine block from defective castings.

Before adding any of these additives I would recommend having a mechanic check the transmission fluid leak to see what the proper repair should be. These additives can sometimes clog systems and make matters worse in the long run.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.