The Stovebolt Site Forums The Shop Area Engine Shop thermostat

Hi all, I was just changing the hoses and antifreeze in my 58, 3600, 235. I noticed a couple of theings. 1. after the engine was running for about 15 to 20 minutes I noticed the was steam coming out of the oil cap. 2 when I changed the top hose from the rad I noticed the thermostat was in crooked. Q1 Is it possible the steam and the crooked thermo are a connected problem Q2. I am wondering if the thermo is in up side down. The thermo is cone shaped and the cone was pointing up like a piramid. Does thids sound right
Thanks Rick

Hy rickyt, The "steam" may just be warm air from inside the engine condensing in the cold outside air. Most thermostats have a cone shape on one side, and a cylindrical shape on the other, the cone shape should be up towards the hose. If you could post a picture of your thermostat we can verify, hope that helps.

There is a little pot or cylinder in the center of the thermostat. that needs to be pointed down into the coolant.

Your motor has a crankcase vent system that uses a pipe terminated underneath to create a partial vacuum going down the road. Fresh air is supposed to enter the oil filler cap and be drawn out down below. When the truck is stationary, non of this happens and the fumes come out the top. All of them produce some blow-by past the rings and this is what you see. The more worn the motor is the more fumes it will produce.

Thanks guys , Ok thanks for this info on the steam coming out. I can stop worrying about that. As for the thermo. I took it out and it is as you descibe it. Little round dish about 3/8 inch high with cone inside. Cone was facing up. The whole thing was a little crooked though. Although I boiled it in a pot (surprised my wife let me get away with that one)Anyway I got the water up to 220 degrees and nothing happeded. I assume it should have popped open. I noticed it may turn rather than pop. either way nothing happeded.

The spring on the thermostat will compress when it opens. You definitely notice when the thermostat opens if you're watching it.

I usually wait till my wife is out of the house to conduct experiments like this.

Hi guys, Ok got a new thermo. replaced all hoses, antifreeze, thermo. Now I have a leak in my heater that I didnt have before. Antifreeze leaking out under truck and onto floor in the cab. Any easy fix I hope
Thanks Rick

What pound-pressure cap did you get? 7 pounds?

still have the old cap. store up here only has 16 lb aqnd up

NAPA should be able to bring in a 7#, just make them look in the Stant catalog

Bill

16#, what is that for; a steam engine? Hahahaha.

Not sure Mr Lang. I'll have to give my old car guy a call to see if he has any 7 lb
Thanks Rick

A higher pressure might cause leaks in a marginal system, designed for a lower pressure (16# vs 7# is a significant difference).

True, that.
If there's a seam hanging by a thread in the radiator or (worse) the heater core this will push it over the edge.

Hi I got a 7 lb cap from napa. Not sure if I blew a hole in the rad or not. I accidentally spilled a lot of antifreeze during all this. Trying to dry it off. Not sure if it is spillage or new hole. I hoping for spillage abviously.Rick

Good luck, Rick

We are all hoping it was spillage. Rinse the spillage off with water and then run it until warm. Give us a report.

Hi guys, you're going to have to be patient with me and excuse my ignorance. BUT, I sprayed some water on what I think is either anti freeze spillage or a leak. Ran it for 8 minutes. Lower hose from rad got quite warm.Upper hose from rad stayed cool. Rad stayed cool. Thermo gauge in dash all of a sudden jumped from cold (left) to hot (far right)Gauge never read very hot before. How do I know what is working and what is not. Dont want to drive and OH and cook something.
Thanks Rick

what's happening is no water circulation, the top hose should be measurably hotter - has it worked since you last had the stat out? sounds like there may be an airlock at the thermostat - or you got it in backwards?

Bill

Yes the other day after I put the new stat in, the top hose, bottom hose, and rad were very hot. I did not check the gauge the other day. I boiled the stat before I put it in and it did open in hot and closed in cold. Directions said spring to motor so I placed spring down. Now what

need to figure out why water isn't circulating, which is the only thing that would give the symptoms you describe .... might try removing the stat and try it without one to see if the pump is working, if it is you should see some action in the top of the rad

Bill

My 216 does this after I have refilled it with coolant. I have to burp it to get the air out since the air trapped behind the thermostat will not cause it to open. I wait until it heats up, shut off the motor, remove the heater hose at the connection near the thermostat, let the hot air escape and jam it back on when fluid appears. One has to be careful to avoid being burned.

I do not know if this was posted above: it is a good idea to drill a 1/8 hole in the thermostat middle "plate" to allow a little coolant to circulate at all times.

Hi, I tried burping it tried taking off top hose. Still gauge went to hot. I have drained it I am going to drill hole in therm after I test it again. I have also looped the heater hose rather than capping them. After i drill and refill I will let you know what happens

actually can youn tell me which way the water shpould be running. Is it out the bottom to engine or out the top to the engine

Ok. did all that now rad is hot, top hose is hot, looped heater hose is hot. Lower rad hose not hot. Temp gauge reads between half and far right (hot). This is after idling a bit high for ten minutes. Am I cured?
Rick

Well it sounds like your thermostat is opening and you are getting proper flow. By the way, the hot water comes out of the top through the thermostat housing, goes down through the rad and is cooled in the process. I would think no more than 180 at idle would be fine.

What do you mean 180 at idle would be fine. By the way it is a 195 therm. I assume tis wont make much differnce

A 160 degree thermostat was standard in a USA 235 in 1958.

a 195 stat is for a V8, if you use your 235 much in winter a 180 will keep the heater working well, and a 160 would be fine for summer with occasional cooler weather use, a 195 is keeping the engine [and lubricating oil] hotter than necessary

the way a thermostat works is to open within a couple degrees of the rated temp and close again if the temp falls below that, a 160 could be cycling in very cold weather unless you have a rad curtain and the engine will be running a bit cool

Bill

So because I only plan to drive in spring summer and fall I better go get a 160. Because I have a 195 is that why the gauge is running about 3/4. Would a 160 bring that down a bit

yes, probably should be around 1/2 or a bit less although the gauges can't really be trusted tell you a lot - with a new-to-you vintage vehicle it's a good idea to check various places with a good infrared laser thermometer to get an idea of how well the system is working and what the actual temp is compared to the gauge

Bill

Well thanks very much everyone. I think it sounds like it is working. I will try to buy a 160 to 180 on the weekend. And I will see about infrared if they aren't to expensive
Thanks again Rick

Thanks Tim

Well guys I put in a 160 thermo and temp is much better.Sits around 1/4 to 1/3 on the gauge. If the weather is good tomorrow I think I just might take er for a spin.
Thanks again everyone.
Rick