So last night I noticed that some coolant was leaking towards the front of my engine (4.9L) in my 1990 F250.

I looked all over the place trying to find the name of the part circled in red (I'm a n00b DIYer). Its not actually pictured in any of the tear down instructions in my handy-dandy Haynes manual. Can someone please tell me the name of it? And does it look like it might just need a new gasket? It looks like there's a metal gasket between it and the head...





Thanks Guys!

 

thermostat housing.

soak the bolts with rust buster.

they break easily.

wpump may be due for replacement.

use a mirror to look under the w.pump at weep hole.

 

Thanks for the info and advice! I picked up a housing/grasket replacement and some PB Blaster yesterday =)

 

May I recommend for possible seized threads, that after soaking with a penetrant lube, try and first crack bolt loose by tightening it, yes, just a quick tighten before loosening it. Found it lowers chances of breaking studs or rounding the heads off.

 

FYI - Be very careful when you put this back together. It is easy to get the thermostat in backwards and it is also very easy to crack the housing. Make sure the thermostat is in the correct position before tightening the nuts.

 

What is the correct position of the thermostat btw? I replaced mine the other night with a 195F and put the new one in just like how the old one went and never gave it any thought....until now.
The reason I changed it in the first place was because it never seemed to come up to temperature (straight up and down) in 'normal' by dash gauge anyways. It stays constantly just before the 'N' in 'Normal', even after a long drive. clutch fan turns without too much resistance(seems normal) and coolant doesn't seem to be low/too high and tested to -30(fine). After replacing t-stat, cleaning t-stat housing temp sensor, problem still persists.

 

pointy part always goes toward radiator.

my big six never went past 'n' until i removed fan and replaced it with elec one.

with no fan rarely reaches 'o' and the fan only had to turn on a couple of time in a year, with no air on.

if air is on the elec fan is switched to always run.

 

If you put it in the way the old one came out you are OK, assuming the old one was in correctly.

Does the dash gauage drop down when the engine is cold?

 

Yes, gauge reads stone cold when cold and slowly climbs to almost just touching the left of 'N' after alot of driving. Pointy end towards rad eh? Then mine was previously installed incorrectly then. I took it out with the pointy end in the head.
I've only had the truck a couple months and it's usually always short around town trips. So it always ran cold since I got it. Perhaps this is the reason?

So you are 100% certain the correct direction of the t-stat on a 4.9L six is pointy end faces the rad? I just don't want to do the job of flipping it around on a hunch. Thanks.

 

i will check my manual to be sure.

on 4.9 pointy side away from block.

ALL thermostats are marked.

copper pellet or element goes toward the engine.

you really should have your own manual to look this kind of info up.

it will pay for itself in one or two jobs.

 

Thanks quicklook2. Sorry for hijacking your thread mrBubble

 

@ 94 shorty, not sure about this but some thermostats have a bleeder kinda thing that always goes at the top.

@ mrbubble: does an f250 really come with a 4.9 six? O.o never seen that.

 

Heh fine with me, its stuff I need to know

Yessir! Didn't want too much power, I'd be getting into trouble...

 

Heh, too much power? Get em on a wheel dyno and most of those old 300-6's made better horsepower and torque than the 302's of the same year....

Not by a huge amount, but enough that you'd notice when loaded/pulling.

 

300s came in large dump trucks too...every ford truck produced during the 300s reign of terror offered the 300...for good reason

if i remember correctly the spring of the Tstat goes towards the block? thats how the 302 was anyway...so if thats wrong i guess it doesnt matter cause it works

also when you throw the Tstat back in give them bolts a bit of the silver anti-seize stuff about half way up the threads...make it nice an easy for next time...i do that with anything i can and trust me, you will thank yourself

when you did that housing and gasket did you put a new T-stat in? should have...its like $7, cheap insurance