Mark71

So I am in the middle of doing a flush (and flush and flush) and fill on my 71 Olds 350. I also put in new heater hoses and upper and lower rad hoses. I'm a little OCD in this stuff - it has to be right.

I opened up the Service Manual to get the torque specs for the water neck housing bolts and noticed on page 6K-7 that the OE one has a "front" and that putting it in backwards can cause all sorts of bad mojo in the coolant flow.

• With my new Mr. Gasket one, there appears to be no front - so does it matter? Or is that little "tang" on the thermostat housing representative of "front"? (pic 2)

• Also, do I need to use any sealant or anything on joint between the water neck and the manifold? Can I get away with "just" the gasket?

Any advice is welcome!

Thanks,
Mark

Lady72nRob71

Never a dumb question! I am OCD like this, too, as I do not want to have to do it over!

If you look carefully at the manual picture, that old t-stat design had a flap that opened, making it not flow well when backwards. The new t-stat designs do not matter as long as the copper rod or spring is down in the engine.

After having installed one of those new Mr Gasket t-stats that was stuck open, I will now check all new ones in a small pot of water before installing.

Check flatness of the t-stat housing using sandpaper on a known flat surface and sand flat if needed.
I am in the habit of always using permatex sealler on both sides of the gasket. I clean the sealing surfaces with alcohol before applying sealer.
Also, sealer needs to be used on the lower threads of the bolts as they go into the water chamber. Lastly, I torqued mine to 15ft-lbs instead of 20 as noted in the manual. My manifold threads were a bit corroded and did not want to torque more than needed.
Never had a leak yet!

76oldswarrior

Your picture from the manual is for the old style thermostat with the flapper on the top. That must open towards the front. But the newer style like you have just needs to put in with the right side up like you have it sitting. Yes you need to use selaer. Thin bead on both sides of the gasket.You also need sealer on the bolt threads. I usually put the bead on the intake smear with finger. Put thermostat in. Then set the gasket on. Then another thin bead on the bottom of the housing smear with finger and set on intake. When smearing with your figer dont smear it off just smooth lightly. I like to smear it so it doesnt squeeze out all over.

rocketraider

Worth repeating that sometime in the early 70s, Olds sent out a tech bulletin advising that they were switching to the Robertshaw type stat in production and discontinuing the old Dole flapper-types. Also recommended switching them out on any older car that came in for cooling system service.

I've developed the habit of chasing those threads with a tap when I do a t-stat job. Not above putting in new bolts either. You ever have one of those bolts wring off, you will become a thread clean-up believer.

Homestar

Tip:
Put an asprin tablet to hold the T-stat open while you fill the motor, it will disolve in very short time.

Mark71

Wow... I am really glad I asked these questions. I would've made a couple of mistakes and wondered why. Just to be sure, the Permatex sealer you are talking about is just the regular old RTV-type stuff, right?

That's a great trick - wouldn't have thought of that.

Lady72nRob71

Hey - great idea! If it reduces my temperature, it should help the engine, too!
(Yes I know, it is to burp the air out...)

No, I have been using Permatex #2 for years - my dad left a bunch LONG ago and I used it on everything ever since. It is a black alcohol based non-hardening sealer. RTV is different, like a silicon stuff.

Warhead

X10 on the permatex. I also will use stuff called Indian head.
It seals water ports far better than sillycone IMHO.
I usually rub the flat side of any thermostat housing on smooth concrete to ensure flatness. Looks like a run on a surface grinder. I have purchased new ones that were warped, this took care of it.

Jim

Mark71

So I pulled the thermostat housing / water neck. I cleaned it up, but noticed it was a little rusty and some paint was coming off. So I figured "Why not repaint it?"

After cleaning it up, I realized I might not be able to finish in time because the paint needs to dry.

I've got the system filled with distilled water right now. Can I leave it that way overnight? Should I drain it? Is it going to rust inside the water jacket or radiator if I do????

rocketraider

It'll come closer to rusting empty than it would with distilled water in it. The radiator is made of brass or aluminum which doesn't rust.

You probably want some non-hardening sealer on the bolt threads too. Non-hardening sealer- not LocTite.

Mark71

Well, as long as I am still working on it, I figured I'd post an update. I know that for most folks on here, this stuff is as simple as it gets - but for those of us that like pictures and a little reassurance... ...here's the info I've put together so far:

The water neck before I removed it looked pretty nasty.



Here's another pic. I loosened up the hold-down bolt for the water neck and realized that there was no way I was putting it back on the engine with all that nasty flaking paint and rust and whatnot.





After lots and lots of cleaning with wire brushes, etc., the water neck looked a little bit better.



That wasn't quite clean enough for me. So I masked off the machined surface and sand blasted it (gently ). Unfortunately, I didn't take a pic of that, but it looked better, so I went ahead and painted it with high-temp engine paint.

In the mean time, I cleaned the gasket surface on the manifold. I used a gasket scraper (again, gently) after covering the port. When finished, I used plenty of alcohol to clean up the surface (thanks for the tip Rob!!!).


I set the Mr. Gasket 180 degree thermostat into place after I realized that the 'stat does have a "front". Look at the pic below - it says "toward radiator" on one side. Also, I tested the thermostat ahead of time in boiling water (again, thanks for the tip, Rob!).



Ok, more pics and info to come tomorrow. Gotta get some sleep now - wife's already yelling at me.

rustyroger

Looks like you are taking the time & trouble to do the job properly, I'll bet your car doesn't let you down unexpectedly much.

The aspirin trick sounds like a great tip, I'll remember that one and pass it round the UK forums like I thought of it first!

Roger.

Lady72nRob71

There should be an arrow next to the "towards radiator" wording that points towards the cone (top) of the 'stat. Once the cone is pointing up, actual rotation does not matter. This created a long thread elsewhere here last year.

Mark71

I figured that since it was completely horizontal it shouldn't really make a difference. Having seen it open in the boiling water on the stove, I knew it opened equally on all sides.

Because I am a little superstitious, though, I made VERY sure it was facing towards the radiator.

Lady72nRob71

I woulld liked to have seen you done that with the one in my Ford engine - it is oriented horizontally so you woulda crushed it in there sideways...
At least the cone points to the radiator...

Mark71

Ok, so I finally got a few minutes to post the last pic of the job I did with this thermostat and water neck. It took longer than I wanted it to, but it seems to work correctly and I've been driving quite a bit since I did the replacement.

Here's how it looked when I was close to finished:


You can see that I am missing the clamps on the water neck to water pump connection, but those got put on afterwards. I know that it should've been Oldsmobile gold, but I wasn't able to find that on short notice, so I decided black would do. I should've painted the bolt heads as well, now that I look at it. Oh well...

I also found that the oil pressure gauge connection (down below and to the right of the water neck) is leaking a bit. It is a slow leak, but it is one of those stupid compression fittings. I'll have to figure that one out soon. I hate those fittings and cheesy plastic hose, too.

Anyhow, the 180* thermostat works perfectly according to the temp gauge and even in the 85+ weather the engine stays right around 180*.

Thanks for everyone who responded and helped me out with this. I appreciate it!

-Mark

Lady72nRob71

Glad its is working well!
I hade comtression fittings, too. All they do is leak.. My Ford's oil gauge line leaks there, too.

BTW, your water pump needs painting now. Come join me on the dark side.............

GAOldsman

I found that if you run copper tubing instead of the "cheezy plastic hose" it will hold up years longer and the compression fitting doesn't leak unless it's loose.

1965cutlassragtop

@ borry....depends on the driving conditions. if your only driving the car during the summer, or live in an overall warm climate, you should run a low temp thermostat...160 will keep it nice and cool, 180 will be a bit warm but will work, 195 would be too hot. but if you drive the car in the winter or in temperaturs that drop below 50 degrees, u would want to run a warmer thermostat....160 would be to cold and not allow your engine to get to operating temp, 180 would be a bit cool but work, 195 would get it nice and warm. i just pulled my 195 out and swapped it for a 160 cuz my car is only a SUMMER weekend cruiser, and i was reaching 210-225 degrees on warm days in traffic. now with the lower stat, it will stay right around 180, and has yet to run over 200, even in stop and go traffic. also, the temperature rating of the thermostat will not directly reflect the temp at which the engine will run, all it does is tell you what temp the thermostat will open to allow cooling through the radiator to begin, so your engine temp will generally run about 20 degrees warmer than the thermostat rating.

Homestar

If it is a summer only car you don't need any thermostat.
Am I right?

hamm36

I would say you are wrong. sorry, jmo.

Cr099

I too had a slow leak in the compression fitting. I replaced mine for $2.00 at local parts store. Don't over tighten!

Lady72nRob71

All cars need a thermostat, even in the summer.

redoldsman

That aspirin trick just proves you are never too old to learn. I never heard of that. As a sidenote, I actually put a thermostate in a Rolls Royce once. It had to come from the dealer. The thing actually had several pellets in it that would melt if the thing stuck closed so you could continue to drive the car.

86Regency

The thermostats Mr. Gasket say Race only, can I still put it in my Oldsmobile 98, I dotn race it, but I drive it around a lot, will it affect it, in a better way o not? Which will be the best thermostat for me, I drive both in Super hot conditions and pretty cold too. Im in Houston.

Homestar

Why would this car need one for the summer?
Thermostats are to let motor build up heat from winter cold temps.
I used to remove mine all the time.
Did I miss something in mechanics 101.

Lady72nRob71

An engine needs to run at a particular temp range to be efficient. PArts need to expand to close the gaps, too. MAny other reasons also. Always run a stat!

The Mr gasket t-stats are only made for certain cars, so not sure if it will work in the 86 Regency. If it fits, then get nothing below a 180 to keep the computer from freaking out, thinking it will not reach operating temp.

86Regency

YEah,it does fit and I am planning on getting the 180 one. Or do you have any other suggestion.

Lady72nRob71

Sounds good then!

Junkman

The manufacturer specs the thermostat based on what they have determined to be the best operating temperatures for the engine. If the engine runs cold, then you will get sludge build up as a result. It has nothing to do with the quality of the oil, or how often you change it. To prove this point, one time I took a freshly rebuilt engine, and after 500 miles, I drained the oil, and pulled the pan. On the bottom of the pan, when you touched it, you could see your finger print in what looked like a film of glue. You have probably seen this as a brown film on the inside of the valve covers, or the pan when you remove it. The cooler an engine runs below its OEM specification, the more sludge build up you will get. It might not be noticable, but it will be there. For this reason, I use the thermostat that is rated for what the manufacturer suggest. I also change oil regularly, and buy the best oil for my type of driving. I have never had a problem with overheating, since I change anti freeze every 2 years, and clean the cooling system at that time. I have always subscribed to the theory that if it worked properly in 1960, then it should still work properly in 2011 if you properly maintain the vehicle. The only variable from 1960 to 2011, is the oil is a better quality (except for the ZDDP being lowered) and the gasoline is of lesser quality.

Squirrel_Assassin

That is an excellent tip! Never heard that one before but I plan to use it today as I am replacing the factory single row radiator with an aluminum 4 row radiator, dual electric fans, new hoses and thermostat. I have heard of drilling a hole in the flange of the thermostat to vent air while filling the radiator but never tried it.
Thanks for the tip Homestar.