help! thermostat change

[kndlindsey]

I can't get dave on his cell and of course i can't remember a thing he told me just 20 minutes ago. I am changing the thermostat.

Do i put the thermostat in first and then the gasket over it and does the thermostat go in with the spring up or down?

Kim

[asdasc]

I was just out doing the same thing to my car. Spring down and then gasket!

[MikeyOne]

It goes in spring down, and the gasket goes in on top. Use a bit of Permatex RTV on both sides of the gasket - they make a grey one for "water pumps and thermostats" that is resistant to coolants.

Personally, I dont use the gasket at all, as it invites water to wick to the bolts, which then rust into the thermostat housing. I put a 1/8 inch think layer of the Permatex and then set the thermostat housing on and start the bolts - but do not tighten them. Then make sure that the sealant has no visible gaps and let it dry for a few hours or overnight. Then I tighten the bolts to about 5 or 10 ft/lbs (do not need to be really tight). This never leaks and the bolts dont rust.

I also usually replace the stock bolts with stainless, again to aviod rust.

[asdasc]

I wanted to get you that quickly, but now for the long answer.

I have been having temperature issues for a while. At first, I couldn't get it to read any higher than the very first bar. It wasn't pegged, like a bad connection, but I couldn't get it to move much. I replaced the thermostat. MAYBE a little better, but still not much. Then I found that I had another sender from my spare engine, so I put that in. Now as the car warms up, them temp keeps rising and modulates up around the last 2 bars (or worse) on the right. I have checked the connection, and it seems secure. I am just now putting the only thermostat in to see if that makes a difference.

I REALLY don't think my car is running that hot. I can still hold my hand to the rubber hoses for 5-10 seconds, and I do most of the test driving in the cool night air (40-50F?).

Any ideas? I can't beleive that I have a blocked radiator just in the last few days, or that the pump is going, as it is still quiet, etc.

I will test drive the recent change back to the old thermostat and if it is still causing greif, I guess the next step would be to check flow on the radiator, and then the engine, and maybe try the pump. I have been reluctant to drain the system as it has good antifreeze in it, and I hate dumping it down the drain (and then buying new!).

[jordan]

Originally Posted by MikeyOne It goes in spring down, and the gasket goes in on top. Use a bit of Permatex RTV on both sides of the gasket - they make a grey one for "water pumps and thermostats" that is resistant to coolants. Personally, I dont use the gasket at all, as it invites water to wick to the bolts, which then rust into the thermostat housing. I put a 1/8 inch think layer of the Permatex and then set the thermostat housing on and start the bolts - but do not tighten them. Then make sure that the sealant has no visible gaps and let it dry for a few hours or overnight. Then I tighten the bolts to about 5 or 10 ft/lbs (do not need to be really tight). This never leaks and the bolts dont rust. I also usually replace the stock bolts with stainless, again to aviod rust.

If the thermostat housing gasket is used correctly it should never leak, and the coolant will never come in contact with the bolts. Also having stainless steel fasteners in aluminium is not a good idea because corrosion is an electrochemical process involving the flow of an electric current, corrosion can be caused by the galvanic effect which arises from the contact of dissimilar metals ie aluminium and stainless steel which are widely separated on the galvanic series chart, an electrolyte is present (engine coolant) which completes the circuit. This situation can make for a mess.

[wrangler]

$10 in anti-freeze is cheaper than engine repair. If you haven't flushed your rad in a while (or ever) now would be a great time to do so before it gets any hotter outside or you find yourself stuck in traffic one day. I tried flushing and back-flushing mine twice, but still could not get it to where I was happy with the temp. It seemed to flow well, and could find no cold spots, but still wanted to over-heat. Finally took it to a rad shop to get it acid bathed and rodded but they said it was so clogged they could not get it to rod well, even after a day in the bath, so I had it recored. That didn't really bother me since I had planned to do that soon anyway when I added a/c. $200 and it now has a larger bore than original (5/8 if I remember correctly).

[wrangler]

Originally Posted by jordan corrosion can be caused by the galvanic effect which arises from the contact of dissimilar metals ie aluminium and stainless steel which are widely separated on the galvanic series chart, an electrolyte is present (engine coolant) which completes the circuit. This situation can make for a mess.

I see that so much down here in FL where it is often damp/rainy with high salt contents in the air. Especially aluminum storm doors that can turn to flakes and dust in a matter of years. It all starts where SS screws have been used into the aluminum. Alot of aluminum enclosures blew away in the canes for the very same reason. Painted steel screws are used to hold the aluminum pieces together, but makes a good supply for those in the recycling business!

[WOOFS-OPEL]

The gasket i.d. should be larger than the thermostat o.d. so it would not matter. Took my cooling system apart last weekend to redo all the cooling lines including removing the lines to the existing water choke on the carb. Broke a bolt on the thermostate housing drilled it out and will now have to use a bolt nut combo - should work fine. Wish me luck, should have the plumbing complete by middle of next week - will the car run with the water choke hoses disconnected?

[hrcollinsjr]

Sure, but not good. See if you can adjust the choke to stay open. It will be a little harder starting. If you're runnning a Weber just convert it to electric. I'm not sure if the Solex lends itself to the conversion as easily has the Weber. The '73 and '74 model cars came with electric choke carbs.

Harold

[asdasc]

Rather than stick in the old thermostat, I just removed it all together. It works great and never gets up to half way on the gauge. That means everything is OK with engine and radiator, so I can now go ahead and put the old one back in and things should be good.

Now, though, I seem to have a charging issue. Rev the motor and the ammeter just keeps climbing! Arghhhh!

So Kim, did you get your issues resolved?

[kndlindsey]

sorry for taking so long but i did start a good discussion! I was impatient so looked up some pics on the net and figured it was thermostat first spring down. I swear the thermo i took out was spring up, but then my mind is failing these days. that is what made me stop,when i took it out i thought, i will look and put it back in the way it came out, spring up, but then i thought dave said spring down. then of course i couldn't remember a word of what he told me and couldn't get him on the phone either.

I got it in and running down the road it doesn't go above 176, barely makes it there. But still wants to run hot, 212 and maybe higher, if you let it sit and idle after having drivien it. If you just start it up and let it idle it stays around 194 or so.

The turbo puts out a LOT of heat and I mean a LOT. I may just be content with what i have. Cant think of anything else to do. It has an electric fan, a stock fan, water wetter and a new 160 degree thermostat.

Got the fuel pump on a toggle switch now. Ran out of time for testing. I shut the fuel pump off and let it run for another 60 seconds or so. We waited 10 minutes and then tried a restart. It fired on the first try but then stalled out since Dave couldn't get the fuel pump switched on quick enough or just because, who knows. and then wouldn't start again and you could smell gas.

Slowly but surely we are working out the bugs. I want to take it to the car show sunday but was hesitant. My friend ed said "does it overheat going down the road?" no. "well, you just have to get there and get home" says ed. He really wants me to go, lol.

[baronbors]

Originally Posted by asdasc Rather than stick in the old thermostat, I just removed it all together. It works great and never gets up to half way on the gauge.

May work good in Michigan but bad idea in Houston.

[asdasc]

Hmmm, I would think that would work BETTER in Houston than in Michigan.

In Michigan, we need the thermostat so that the car warms up faster during the winter. When it is really hot out, the thermostat is wide up once the engine gets up to temp.

The only thing I can think would support your hypothosis would be that you need to slow the water flow down in the radiator to allow it to lose more heat. But I wouldn't think that is right. I am curious to hear others opinions on the matter.

I think I WANT my car to run a little warmer than it does, to make it more efficient. Therefore, putting in the thermostat will slow the flow to the engine, making it run a little hotter.

I think.....

[baronbors]

Seems to me there was a long series of discussions- Water compression- thermodynamics- water heat retention in a thread about 2-3 years ago on this site ( I think it was this site- it is he11 to get old) I don't think the controversy was ever resolved, but here in Houston no thermostat on highway driving OK -just don't get stuck in a 45 minute to an hour traffic jam (which happens alot)or you will be walking real quick.

[opelwasp]

The problem with not having a thermostat is 2 fold. One, the coolant will pass too quickly through the radiator to take advantage of its primary function; to spread the coolant over a large surface area and allow the heat to be drawn out buy the flow of air through it. Therefore the engine will heat up quickly and keep heating up. The coolant also wicks heat away from the engine primarily from the combustion chambers and head. The spark plugs are designed for a specific heat range and if they can not transfer enough heat to the head and it be dissipated to the coolant they will not operate properly and have a tendency to foul. An overly hot engine tends to run like crap, if you have overheated one you know what I mean. Even NASCAR drivers who dont use thermostats, do use a restrictor to slow the flow but not the volume.

[soybean]

Kim, The spring goes up.
If you want to test the thermostat, pull it out and put it in an old pot heat to boiling. Use a meat thermometer to see what temperature it is when it opens. Also watch the spring when it opens, you'll see it rise (up)
I'm running a 180 degree thermostat in my stock 72.
Check out the 1973 Service Manual that is available for download here on the site. HH, Jarrell

[soybean]

Too little coffee this Am and was notified I had posted incorrectly. The spring goes down. The arched piece goes on top. The element sets in the engine side of the water. Sorry, brain was on pause. Jarrell

[asdasc]

Whew. I was worried that I gave bad advice, and worse yet, that I have been doing it wrong all along!

Thanks for the correction. I was going to go do some real studying of flow and the little arrow on the side of the thermostat.

[BritNicholson]

I would be suprised if reducing flowrate through a radiator would ever increase heat transfer out of the coolant, since heat transfer (in or out) is equal to mc times change in temperature, where m is mass flowrate of the coolant. That means if flowrate goes up, the transfer of heat from whatever is hotter to whatever is cooler goes up; in this case, as flowrate through the radiator goes up, the coolant gives more of its heat to the radiator, which then transfers its heat to the air going through it.

[opelwasp]

It takes time for heat to dissipate. The less time the coolant is in the radiator the less heat can be transferred. A radiator is not a filter it doesn't filter out heat, so faster is not better. Coolant has to spend quality time in the radiator to do its purpose. It is about thermal efficiency. It flows to fast not enough heat will transfer out, flows to slow heat will build up, with a thermostat it flows just right.

[jordan]

Ironically I had to change the water pump in the gt today, and when I took the radiator out I heard a rattling inside it and found out it was the mercury or the bimetal actuating part of the thermostat in the top of the radiator so I say to myself 'ohh no, not again' because 3 years ago for some reason the thermostat broke apart and traveled to the top of the radiator and I had to fish it out, so I take the thermostat cover off and it is intact...strange, it must have been that I didn't get it all out 3 years ago, stranger yet I actually found the box that I had the dismembered thermostat from last time in and all of the pieces were there, so I can only assume that a thermostat has broken apart more than once in my engine...anyone ever have this happen?

[opelwasp]

I've never had that happen, sounds very possible though. I only use Super Stant thermostats though. They are much better made than the "el quicko cheapo" thermostats. To me the few bucks more is well worth the peace of mind.

[RallyBob]

Originally Posted by opelwasp Even NASCAR drivers who dont use thermostats, do use a restrictor to slow the flow but not the volume.

Yea, we found out that to make a high specific output (1.47 hp per cubic inch) Opel engine last for circle track racing we had to,
A) Install a larger aluminum radiator
B) Reduce the waterpump speed to avoid cavitation at +9000 rpms
C) Eliminate the thermostat and use a 7/8" restrictor in the thermostat housing.
We experimented a lot with everything from 5/8" ID up to 1-1/8" ID restrictors and the 7/8" kept our engine the coolest for our engine and rpms (190 degrees at WOT at 9000 rpms for 15 minutes four times per day). A quick calculation put our water pump rpms at 9990 if we kept the stock pulley arrangement....with the underdrive pulleys we had 6593 rpms water pump speed with 9000 rpms crank speed. I should someday measure the flow of a stock water pump to see what's really happening here.

That said I generally run a thermostat on all my street Opels. I like the 172* version. In street driving if the engine gets above 195 degrees I get uncomfortable and squirm in my seat. If it breaks 200 degrees I'm genuinely concerned. When it hits 210* I will shut the car down. One trip to 230 degrees is usually all it takes to crack a cylinder head, so I don't want to go there!

Oh, and in dyno testing the CIH makes the best power between 185-190 degrees. At 200 degrees we saw an 8 hp drop. Opels do NOT like heat!

Bob

[tekenaar]

Originally Posted by MikeyOne It goes in spring down, and the gasket goes in on top. Use a bit of Permatex RTV on both sides of the gasket - they make a grey one for "water pumps and thermostats" that is resistant to coolants. Personally, I dont use the gasket at all, as it invites water to wick to the bolts, which then rust into the thermostat housing. I put a 1/8 inch think layer of the Permatex and then set the thermostat housing on and start the bolts - but do not tighten them. Then make sure that the sealant has no visible gaps and let it dry for a few hours or overnight. Then I tighten the bolts to about 5 or 10 ft/lbs (do not need to be really tight). This never leaks and the bolts dont rust. I also usually replace the stock bolts with stainless, again to aviod rust.

. . . and where does one get that intelligent Permatex that goes on in think layers?!

[maglinjosvinn]

hmm
i'm using a low temp thermostat in my car... when ihave the heater on the needle never goes very far up the guage (and hot air is in short supply from heater btw) been that way sincei brought the car home the first time. maybe i'll grab another thermo and see what it does for the car's performance. i think i got the 160deg. not sure anymore. lol.

time to play i guess. been in the house too long on my day off. its that or i'm fixin my horns today. heh.