jer1991

1991 ford f150 (xlt lariat) 4x4, 5.0. I am trying to replace the thermostat.
The two bolts that hold the housing are in a very difficcult location to get a wrench on. Is there some special tool or trick to get at these bolts.
thanks for any suggestions.

1991F150

I'll reitterate this post because I'm having a heck of a problem with trying to replace the thermostat on my '91 302 engine. I have a pretty good selection of wrenches, (no stubbie though) and I can't get either a 1/4" drive or a 3/8" drive socket on the lower bolt. Note that the socket is to long to fit in there. My normal box wrenches are to long as well, the distributor sits within 5 or so inches. I've owned this truck since new and I can't remember ever replacing it before. The truck only has 49K on it so it sits alot. This one has really got me stumped any help would be appreciated. I may check Advance Auto later for some stubby wrenches they said they stocked.

DixieDarkhorse

ratchet wrench? i don't remember it being to difficult but its been awhile

dewman

From the picture in my Haynes manual, I cannot see why you would not be able to reach the thermostat housing bolts. They seem to be reachable with a long extension on a short socket. I can see the distributor to the right of the housing, but I cannot see that it would stop you from accessing the bolt. Perhaps you could post a picture of your engine so we can see what you are dealing with?

twrh111

i replaced my thermostat today in my 94, 5.0. after removing the top radiator hose and the short water pump hose, i could get a socket with extension on the left bolt but the right bolt could only be gotten with a 6 inch box end wrench. like you said theres not much room on that one. but mine was easily enough removed.

1991F150

I know by my post it sounds like I'm inept but it is a very tight area. Dewman, the Haynes picture may be a little misleading because the lower right bolt is down a little behind the water pump housing and you can't go straight in. If one or the other were about 1/4" difference it would probably be enough to use either a universal or go straight in with a socket. Neither my 3/8 drive, 1/2" socket or my 1/4 drive, 1/2" socket will fit between the bolt head and the back of the water pump housing. A previous post by someone said to remove the two hoses from the air filter, and that opened the area up quite a bit. I went down to Advance auto and bought a set of stubby wrenches, $15 or so, both metric and SAE. The 1/2" wrench is about 4 1/4" long and it fit in on the bolt and would move a little at a time. Took about 20 minutes to get that one bolt out. It was all corroded/crusted up so I cleaned both bolt threads up with a die. After cleaning the gasket surface real good I ran a clean 5/16 x 18 bolt in to clean up the thread area. Both bolts should go in a lot better than they came out. I'm sure I have never replaced the thermostat before.............I'd remember this much pain! So the bolts haven't been out for almost 18 years. It is all ready to go back together but I have some family home for a short while so I'll finish up tomorrow. Thanks for all your help. Now I hope I don't crack the goose neck going back together. I'm wondering if I should put some never seize on the two bolts. Anybody got an opinion on that? Thanks.

Just call me Sean

iTrader: (1)

Yes, put anti-sieze on the bolts.

1991F150

Thanks Sean, I'll try it.

Just call me Sean

iTrader: (1)

Just so you know, anything that threads into aluminum needs anti-sieze on it, because steel reacts with aluminum and corrodes the parts together. I use it for just about everything now so I don't have any trouble later.

mitchalvin

I bought a flexible handle screwdriver that has a 1/4 inch socket mount on it, then with the proper socket you can use this to tighten or loosen the bolt after breaking it free with a end wrench, you will have to torque it down with a end wrench or the gasket will leak.