Underdrive Pulleys

[NJH_Habitatpro]

Hey im thinking of getting some for my 89 mustang LX 5 speed. Fully loaded. Would they hurt my car any like heating up wise or anything like that. I know its makes it easy on the engine a little i just dont know.

[jckorn311]

nah it wont hurt any of it if anything itll make it run better as far as heating its a big plus in my car

[ScottyB1]

If you live in an area of the country where you have particularly hot summer weather, you may see your operating temperatures get too high. This will only happen if you are sitting in traffic with the engine idling. While the engine is running at a decent rpm you will not have any problems. However, you do loose some engine cooling power at lower rpm. This could be solved by a new radiator also. The underdrive pulleys do give a noticable power increase. I have successfully run mine for about two years and have never overheated so it can be done. I do not live in a large city, so I don't have to deal with hours of traffic on end either. You just have to be aware of the possibility.