I noticed my truck (85 F-250 w/ 351w) was giving off a smell of burning coolant, at first i thought it was a heater core, but it wasn't. No coolant was under the truck when I parked it at night. While driving I smell the coolant after the truck warms up, the tem gauge goes up (never out of the normal operating zone), but then settles down and the smell goes away. I popped the hood yesterday and saw a puddle of coolant around my distributor. THere is sore of a divet area where the distributor sits. I'm just wondering where this coolant could be coming from, I haven't had a chance to look to hard since it is raining out. Anyone have any suggestions?

 

First thing that comes to mind is the thermostat housing or ones of the hoses to it.

 

let me ask you a question. I looked at it before and saw it dripping from a part that has a neck on it where the hose goes, and it attaches to the intake manifold. Is this the thermostat housing? The only thermostat i've ever done was on a gm 305 so it looks different. But if thats a thermostat housing, thats the culprit. Am I (actually you) right?

 

That is the thermostat housing. And Fords are a pain in the butt. The thermostat sits in there vertical, so it's very easy for it to slide down when you are installing it, and it will get caught underneath the housing. You don't know this, tighten down the housing, and the best senario is you have a leak. The worst is you crack the housing.

I try to put a little bit of wheel bearing grease or a little bit of sealer to hold the thermostat in enough till I get the gasket and housing installed.

 

Put the thermostat into the housing, attach the gasket to the housing with a suitable gasket sealer.

A length of mechanics wire through the thermostat and passed up through the neck can also be used to temperarily hold the thermostat in.

Make sure your timing cover hasnt rotted out. I have owned more than one Ford small block that rotted the housing.

Here is what happens. Water goes from an iron block through an aluminum housing and into either an iron or aluminum water pump. The combination of disimular metals and water is perfect for a galvonic reaction especially if the water you put in has the wrong chemistry. Never flushing the system can cause the same problem.

 

thanks for the replies guys, ill take a look at it again tomorow and get the parts i need. If i understand correct, I need a new housing and a new thermostat?

 

You might only need to tighten a hose clamp.

However, for the age of the vehicle, you may as well replace the housing, thermostat, all hoses connected to the housing (heaterhoses, bypass hose, upper radiator).

$10 for the thermostat housing,
$15 for the upper radiator hose (same for the lower, while you're there),
$ 5 for the bypass hose,
$12 for 6 LF of "by the foot" heater hose,
$ 7 for the thermostat,
99 cents for the gasket,
$ 4 for an assortment of hose clamps.

Depends how much time/bucks you're willing to spend.

May as well flush the radiator and engine while you're at it. It's not impossible that 20 years build-up of deposits may be giving you grief now.

Sounds a little pricey for a little leak, but remember your ride is 20 years old. Some of that stuff is probably still factory, so it truly is cheap insurance to replace it.

If you replace the thermostat, MAKE SURE you get the kind that fails with the valve open. Costs a couple dollars more, but sooo worth it.

Munrow

 

Thanks, sounds good munrow, i'd rather spend the money now for preventative maintenance than on new heads or a new engine down the road.

 

The water here is so bad on cooling systems that I usually take out my radiator (if the coolant is being drained out anyway and the vehicle has over 75,000 miles) and deliver it to a local shop. They take it apart, clean out all the passages and straighten any bent fins and hose necks. After they solder the whole thing back together they pressure test it. The last time it was only $100.00. After I reinstalled it with the new hoses etc my trucks temperature problems went away. No real surprise considering half of the passages werev not passing any coolant.

As for a thermostat housing, if yours isnt rotted out, save $$ and use the old one. Dont forget to use a good silicone sealer and use antiseaze on the bolts.

Another old racers trick is to use two thin hose clamps butted side to side (you place the tightening screws on opposite sides of the neck) rather than one thick hose clamp. With the two clamp trick you dont have to tighten them nearly as much to seal the hose so you rarely strip them out.

I agree with munrow about the Fail-Safe thermostat. They are cheap insurance against overheating due to a stuck thermostat.

If you really want to save yourself another headache down the road, put in a new water pump while the radiator is out.

 

That is a good reason to go to the store and buy some distilled water for the radiator. I have very hard water where I live too.

 

Well, I'm at college right now so this repair is going to be done with minimal tools in a cold parking lot, so i don't think ill be dropping the radiator, at least not until i go home for thanksgiving. Could it be possible that it is simply the gasket around the thermostat housing that has worn out, and i can just slap a new gasket on there (Just to get me home for thanksgiving)?

 

If you are in that situation, you may want to leave it alone till you get home. Just keep an eye on it and the water level. If it starts getting bad, you can run it with the radiator cap loose, and that should help the leak. It's cooler out now, so running the cap loose should not hurt anything.

 

"Could it be possible that it is simply the gasket around the thermostat housing that has worn out, and i can just slap a new gasket on there (Just to get me home for thanksgiving)?"

Sometimes its very hard to tell where a leak is coming from with out seeing it start. A tiny hose leak could be spraying water to another part of the area, etc.

Go ahead and clean the area well with some hot soapy water. I use 99cent a can starting fluid from Big Lots. Works perfect to clean anything, so far.

Dry the area well, hoses especially (another good thing about the starter fluid, evaporates entirely). Make sure your radiator is filled with a high enough content of coolant to be easily noticed when it leaks.

Start the engine and let it build up pressure (leave the cap on). Maybe rev it some with the carb linkage so you can stay at the engine compartment.

You should be able, sooner or later, to see the exact part that's leaking.

Most autoparts stores have some kind of after-market coolant recovery system you can add to the overflow outlet on your radiator for around $10 or so. It'll extend the period of time you can go (trip home?) without having to refill radiator. Makes it easier to fill when hot, too. You must get the correct cap for this system to work.

As to having the radiator fixed, after "brushing someone off the street" last June, I got a new, 3 core OEM replacement, with a 3 year warranty from the autoparts store for $168. When you get one fixed for $100 or so, you still have a 20 year old radiator with no warranty.

The only tools you need for the hoses and thermostat are a 1/2 inch wrench(depending on your set-up, maybe a 7/16 inch wrench), a screwdriver, and a tiny dab of sealant to hold the gasket in place. My own preferred method is to put a tiny bit of silicone arounk the gasket surface the housing, wipe off whatever sticks above the flange, press the gasket in, wipe again, let dry most of the way. Haven't had any slippage since doing it that way.

Munrow

 

Well the only reason i was mentioning the radiator was because hatch had said something about a rotten timing cover, and bad water etc in the radiator. For now, I just want to stop the leak I have, which is coming from the thermostat housing or possibly the hose. Tomorow I will check it out because the weather is supposed to be nice. If this is the case (thermostat housing), I'll throw a new housing and thermostat in the truck, and if its the house (which would be soooo nice) ill obviously just change the house. As for anything else like the timing cover or other parts, once i get the bad boy home ill let my friend (certified mechanic) take a look at it. From what i saw from the brief time i ran the truck the other day, the leak was coming from the thermostat housing, so im just going to replace that and let it be. Thanks to all you guys for replying!!

 

If the thermostat housing has rotted out and is leaking take a very close look at the top of the timing cover as it is also aluminum and likely to rot out.. There are two passages through the cover that pass water from the block to the water pump. When looking down at the top of the timing cover, they look like "humps" on the top outside of the cover. Inside of the "humps" there are "valleys". If the valley has a bunch of stuff that looks like a whitie powder your timing cover is leaking, replace it. While in there put in a new timing chain and sprocket set.