billball

When I turn off my truck on hot days, sometimes a blower will come on for a period of time. Is this some sort of cooling blower? I have a 89 F150 with the 4.9 liter engine.

88xlt

Yes it is some sort of cooling blower. It must have been put on the earlier fuel injected 4.9s. My '88 has one.

Just call me Sean

iTrader: (1)

4.9s get that fan.

unit505

Until when? Not present on the '95. Seems like I read 91?

Just call me Sean

iTrader: (1)

Pretty sure all of them. People do like to remove them because they don't know what it's for.

unit505

Nope! My 95 never had one.

unit505

Okay....it's an obsolete part. Fuel injection cooling fan/anti vapor lock fan. Used on early 4.9's to cool the injectors and avoid vapor lock. Looks like 87-88. What little I could find about it says that the fuel pressure was raised in later years from 40psi to 60psi and this fixed the issue and the fan was discontinued. Possibly a recall item. After shutting off the truck, the fuel rail would be hot causing the fuel to vaporize. The fan initially solved this until fuel pressure was raised.

unit505

https://www.f150forum.com/attachment...r-100_5680.jpg

Just call me Sean

iTrader: (1)

I'm not arguing. You did more research than I.

unit505

Well...I searched and searched for better info. This was, maybe by you, posted on the forum not so long ago. I'm surprised just how little info is out there. Sounds crazy, but I guess the first run of F.I. 4.9's had vapor lock issues and then this bower came along. I get that the 4.9's fuel rail is closer to the exhaust than a V8, but the 4.9 had better airflow around the block than the V8. I can't find this blower anywhere for sale or even in the discontinued parts list. I guess maybe a recall took place and they changed the fuel pressure regulator? The one article I found said that the fuel would vaporize at 40psi, but not at 60psi. Strange. Even rock auto turned up nothing.