Degsy Posted January 15, 2012 Share Posted January 15, 2012 This might be a stupid question, but before we get all excited about thermostats are we sure it isn't just a faulty temperature gauge? Does the engine feel as though it's up to working temperature? Andy Not a stupid question, it is possible but the symptoms are fairly classic for a faulty or missing themostat. Quote Link to comment Share on other sites More sharing options...
Vulture Posted January 15, 2012 Author Share Posted January 15, 2012 This might be a stupid question, but before we get all excited about thermostats are we sure it isn't just a faulty temperature gauge? Does the engine feel as though it's up to working temperature? Andy Andy Up until this last journey everything was behaving normally. (I take the truck out, the engine gets warm, the temp gauge goes up after a while and I get warm air blasted up my right leg through the hole in the floor where the winch lever is ! :laugh:) That said it has never been a truck (in the 6 months I've had it) that has gotten really hot, normally the temp gauge reads around 140 to 150 when your travelling along. This was out of character.... although the engine seemed to be running fine on the trip. There wasn't the normal heat coming up through the floor, but I put that down to the cold day. What I still struggle with is the speed with which the temp gauge dropped back down to 100, I mean it seemed to happen with a second or so of turning the engine back on :confused:. I intend to try and replicate things tomorrow and take photos/vid as it happens. I fully expect the engine to throw out the excess water in the rad, but filling it to the top, was the only way to find out at what level the water had been at when this snag happened. Kind regards Ian Quote Link to comment Share on other sites More sharing options...
deadline Posted January 16, 2012 Share Posted January 16, 2012 Where are these air tight t-stats coming from? How you creating a vacuum in a pressurized fluid? The t-stat is BELOW the full level of the radiator. The t-stat is not air tight. How are you creating these air pockets/vacuum chambers? Cardboard? Are you ready for the TM cite? TM9-801 April 1944 page 221: Sorry, I don't have a part number for the card board. :-D:cool2: Quote Link to comment Share on other sites More sharing options...
deadline Posted January 16, 2012 Share Posted January 16, 2012 Get modern water temp gauge and plug that into the block. The bourdon tube in the temp gauge may be out of adjustment and require re-bending to get the gauge to show the proper temp. Then engine temp should only be 180-ish. A working t-stat starts to open at 160. If you think the t-stat is stuck open (that's a very rare failure mode... they typically fail to open and overheat the engine) a simple test: Engine cold. Remove radiator cap Start engine If cold engine shows radiator coolant moving (you can easily see it being circulated) then the t-stat is open when it should not be. Are you sure you have a t-stat installed? DO any of the radiator hoses get HOT when at fast idle? It should not take more than 10-20 minutes to get the coolant to 180F I recommend cardboard!!!! Quote Link to comment Share on other sites More sharing options...
griff66 Posted January 16, 2012 Share Posted January 16, 2012 the two faulty thermostats ive had were both stuck open ie ages if ever to warm up then correct temp in traffic soon as u move off again temp drops off, think stuck open is the most common fault mode ,very nice my cardboard! Quote Link to comment Share on other sites More sharing options...
Degsy Posted January 16, 2012 Share Posted January 16, 2012 Yep, I agree with you Griff, in the many years I have been repairing vehicles have changed a lot of thermostats that were stuck open. On modern vehicles the usual customer complaint is 'my heater doesn't work'. Some models are prone to airlocks if the coolant has been allowed to go low and then refilled without bleeding but thermostat failure in the open position is not uncommon. Quote Link to comment Share on other sites More sharing options...
Vulture Posted January 16, 2012 Author Share Posted January 16, 2012 A short update guys. Rang up Rex Ward, got chatting with him, and his immediate reaction was (like many of) that what I was seeing were the classic symptoms on a CCKW of the Thermostat being stuck wide open. I've ordered a new Thermostat, gasket, and top hose off him, all of which will hopefully arrive for the weekend. I've decided to leave the truck as it is for the moment, and attack it at the weekend. Kind regards to all Ian Quote Link to comment Share on other sites More sharing options...
Tony B Posted January 16, 2012 Share Posted January 16, 2012 Good excuse for fresh anti freeze then? Quote Link to comment Share on other sites More sharing options...
Vulture Posted January 16, 2012 Author Share Posted January 16, 2012 Good excuse for fresh anti freeze then? It would be if it wasn't for the fact that I changed it all over about 6 weeks ago ! LOL Hey ho, its going to be out with a bucket collecting it from the drain on the rad front Quote Link to comment Share on other sites More sharing options...
Tony B Posted January 16, 2012 Share Posted January 16, 2012 It would be if it wasn't for the fact that I changed it all over about 6 weeks ago ! LOL Hey ho, its going to be out with a bucket collecting it from the drain on the rad front Damm right! At the cost of the stuff! But why does there always seem to be more coming out than you thought you put in? Quote Link to comment Share on other sites More sharing options...
Vulture Posted January 16, 2012 Author Share Posted January 16, 2012 Damm right! At the cost of the stuff! But why does there always seem to be more coming out than you thought you put in? LOL ! I know what you mean Quote Link to comment Share on other sites More sharing options...
deadline Posted January 16, 2012 Share Posted January 16, 2012 Just thought I'd clean this tread up and dispell some myths: T-stats have vent holes, no way air/vacuum can be trapped: Does a CCKW t-stat FAIL to the open position (by design, like modern ones) or it simply can break and randomly be open or shut? Quote Link to comment Share on other sites More sharing options...
Vulture Posted January 22, 2012 Author Share Posted January 22, 2012 (edited) Gentlemen An update for those kind souls who have taken an interest in this thread and the connected one about an expansion bottle question I raised. The Thermostat and gasket (s?) and top hose came in the post during the week, and with a break in the rubbish weather this morning was as good an opportunity as any to (attempt to) sort this snag out. Here's the new bits: I've been sent two gaskets, I expected just one, so a bit of a puzzle straight away for the NOOB here as the manual only mentions one. To help us consider the scenario, here's a couple of gratuitous engine shots of the offending area With the cap off here's what I see. And here's the cap, not a fibre washer that some have mentioned in sight. Should be one there on this type ? Anyway, the top hose comes off after a short fight, and the top housing unbolts without difficulty. This is what we find......... WTF ? No Thermostat... So I look to fit the new one, and have an immediate question for the more knowledgeable souls. Does the gasket sit underneath the Thermostat, or on top of it. Either way when I put the housing back on top, it is not a snug fit, and there is a gap all the way round... Is that normal ? I think the Thermostat is meant to sit on top of the gasket, but I wait your wise guidance before I try bolt it back in place. Also what is the small gasket for ? Is that mean to sit on top of the thermostat (it definitely won't fit underneath) ? Kind regards to Ian Edited January 22, 2012 by Vulture To add photos Quote Link to comment Share on other sites More sharing options...
deadline Posted January 22, 2012 Share Posted January 22, 2012 (edited) Um... your cooling system looks HORRIBLE. None of the that rust should be there. You DO have the gakset... its the red thing with the lip pressed into it. Look at the hole for the overflow tube... you can see the edige of the gasket there. Compare to mine... I have no gasket I wouldn't put parts in or troubleshoot anything until you get that radiator cleaned. You may want to get the ENTIRE cooling system flushed. That's bad.. really, really bad. Like its been run on plain water, not anti-freeze. No rust! And no gasket either Edited January 22, 2012 by deadline Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted January 22, 2012 Share Posted January 22, 2012 You DO have the gakset... Compare to mine... I have no gasket And no gasket either Oh well, Deadline, looks like you have learnt something today Quote Link to comment Share on other sites More sharing options...
N.O.S. Posted January 22, 2012 Share Posted January 22, 2012 .....That's bad.. really, really bad..... :shocked: A tad on the alarmist side maybe, Deadline old chap? I suggest it might be more accurate to say - "That's dirty..really,really dirty! Looks just like every Forson Major radiator I've seen Typical working engine methinks. No worries Vulture. Plenty of my engines were like that but they usually clean up fine. Yes I'd certainly agree with Deadline it could do with a good flush through. If you take off the bottom hose off the radiator once the engine is flushed right thorough you'll be able to see what comes out of the radiator and at what flowrate. It should cope with a normal garden hose flow, if it doesn't it must be partially blocked, you could try one of the automotive cooling system flush products (a Watneys Party Seven would have done the trick.....). Quote Link to comment Share on other sites More sharing options...
Tony B Posted January 22, 2012 Share Posted January 22, 2012 (edited) Time to close system up, without thermostat Get a bottle, or three, of decent radiator flush. That will start another argument as to which one. Flush system . Then remove bottom hose , wrap rags round a hose pipe stuff into bottom of rad and back flush. I now have a De humidifier! That provides me with nice clean soft water for re-filling radiators, rain water is the other old chestnut, but catch in a clean plastic container. I also add K Bar conditioner to the mix and leave it in. With the state of the system new rubber hoses would be a good idea. Quick Note: Some vehicles can be touchy were the thermostat relif hole is positioned, don't know on your one. Edited January 22, 2012 by Tony B Quote Link to comment Share on other sites More sharing options...
griff66 Posted January 22, 2012 Share Posted January 22, 2012 seen worse as stated flush with water then rad cleaner then refill 50/50 with water blue antifreeze then change it again in 100 miles Quote Link to comment Share on other sites More sharing options...
Vulture Posted January 22, 2012 Author Share Posted January 22, 2012 Um... your cooling system looks HORRIBLE. None of the that rust should be there. You DO have the gakset... its the red thing with the lip pressed into it. Look at the hole for the overflow tube... you can see the edige of the gasket there. Compare to mine... I have no gasket I wouldn't put parts in or troubleshoot anything until you get that radiator cleaned. You may want to get the ENTIRE cooling system flushed. That's bad.. really, really bad. Like its been run on plain water, not anti-freeze. [ATTACH=CONFIG]56012[/ATTACH] No rust! And no gasket either Ahhh, the penny drops ! When I spoke with Rex Ward last week we talked very briefly about a new Rad cap and seal, but he said he didn't have either in stock at the moment, so I assumed incorrectly that the red seal must be to do with the Thermostat. He must have found one, and thrown into into the box for me . The picture makes the condition of the cooling system look worse than it is, it has to be said. Quote Link to comment Share on other sites More sharing options...
Vulture Posted January 22, 2012 Author Share Posted January 22, 2012 (edited) Okay guys I'm picking up the vibes here that a flush of the cooling system might be in order before putting the Thermostat in. I'll pick up some suitable flushing agent from the local garage tomorrow. Have to say though that on the previous drain down I did, and again today, the water/anti-freeze mix was very clean. Like I say I'm not adverse to giving it a flush. I'll follow the advise several of you have kindly given. I'll also get a new bottom hose of Rex this week, to compliment the new top one. But guys, what about the Thermostat gasket question ???? When I get round to re-fitting it (after the flush), do I fit it on top of the Thermostat or below ? Looking at the old gasket I reckon it was under the Thermostat... (when it had one fitted) Question: When the housing is bolted down does it very slightly 'crush' down the raised Thermostat lip ? Kind regards to all Edited January 22, 2012 by Vulture Quote Link to comment Share on other sites More sharing options...
Degsy Posted January 22, 2012 Share Posted January 22, 2012 After all the alarmist and misleading (however well meant) comments I really don't think you have anything to worry about, I've seen far worse than that on many occasions and they've flushed out okay. After a good clear out and the new bits fitted I'm confident you'll be okay. Best of luck with it and keep us posted. Quote Link to comment Share on other sites More sharing options...
Big ray Posted January 22, 2012 Share Posted January 22, 2012 I always used to put a couple of handsfull of Soda Crystals into my rad at the beginning of the show season, run the vehicle for that season, then flush the system. It always did the trick for me, and kept the system clean. Just a thought. (When I say that I used to do this..... I dont get out so much now.) Quote Link to comment Share on other sites More sharing options...
Vulture Posted January 22, 2012 Author Share Posted January 22, 2012 After all the alarmist and misleading (however well meant) comments I really don't think you have anything to worry about, I've seen far worse than that on many occasions and they've flushed out okay. After a good clear out and the new bits fitted I'm confident you'll be okay. Best of luck with it and keep us posted. Thanks for that Degsy :-) Quote Link to comment Share on other sites More sharing options...
JOURNEYMAN Posted January 22, 2012 Share Posted January 22, 2012 Hi vulture, when you re-fit the thermostat make sure you clean out the small circular recess in the top of the thermostat housing. The new thermostat goes in next ,( the circular plate sits flush with the top of the thermostat housing ).the new gasket then goes on top , followed by the top half of the housing. From memory the inner hole of the gasket is slightly smaller than the round disc of the thermostat and helps to hold it in place. The inside of my gmc engine looked rusty but after it had been flushed through a few times it was ok. One thing i did find was that dirt had collected at the back of the engine and had to be removed by removing the drain plug on the rear of the block ( driver,s side ), and poking around with a length of stiffish wire. The block had to be flushed again to wash the muck out through the drain hole,i also flushed the block out by inserting the hose in the drain hole. Don,t forget to replace the drain plug... Fill up with 50/50 pre-mixed blue anti-freeze, i used bluecoll which has given no trouble. I put as much liquid as i could into the engine/radiator, then started the engine to allow it to circulate and to give any excess air a chance to escape,( i have a thermostat fitted which has a "jiggle pin " in it to allow air to escape from the block.) i then topped up the radiator until it was just visible in the neck of the radiator. I then replaced the cap, making sure it was sealing correctly.after a while the excess water vented itself from the tube on the side of the radiator ,stopping when the radiator had found it,s " own level " i always make a point of filling the radiator as described with 50/50 pre-mix and let the radiator vent itself. Don,t forget to flush the radiator as well, i took mine off, sealed the bottom opening with rags, left the radiator cap on,poured in 2 litres of de-scaler, followed with boiling water until full and sealed the top hole up with rags. This was left overnight and flushed several times the next day. Hope this helps. Steve Quote Link to comment Share on other sites More sharing options...
Degsy Posted January 22, 2012 Share Posted January 22, 2012 Hi vulture,when you re-fit the thermostat make sure you clean out the small circular recess in the top of the thermostat housing. The new thermostat goes in next ,( the circular plate sits flush with the top of the thermostat housing ).the new gasket then goes on top , followed by the top half of the housing. From memory the inner hole of the gasket is slightly smaller than the round disc of the thermostat and helps to hold it in place. The inside of my gmc engine looked rusty but after it had been flushed through a few times it was ok. One thing i did find was that dirt had collected at the back of the engine and had to be removed by removing the drain plug on the rear of the block ( driver,s side ), and poking around with a length of stiffish wire. The block had to be flushed again to wash the muck out through the drain hole,i also flushed the block out by inserting the hose in the drain hole. Don,t forget to replace the drain plug... Fill up with 50/50 pre-mixed blue anti-freeze, i used bluecoll which has given no trouble. I put as much liquid as i could into the engine/radiator, then started the engine to allow it to circulate and to give any excess air a chance to escape,( i have a thermostat fitted which has a "jiggle pin " in it to allow air to escape from the block.) i then topped up the radiator until it was just visible in the neck of the radiator. I then replaced the cap, making sure it was sealing correctly.after a while the excess water vented itself from the tube on the side of the radiator ,stopping when the radiator had found it,s " own level " i always make a point of filling the radiator as described with 50/50 pre-mix and let the radiator vent itself. Don,t forget to flush the radiator as well, i took mine off, sealed the bottom opening with rags, left the radiator cap on,poured in 2 litres of de-scaler, followed with boiling water until full and sealed the top hole up with rags. This was left overnight and flushed several times the next day. Hope this helps. Steve All good advice and a nice clear explanation, follow that Ian and I'm sure you won't go wrong. Quote Link to comment Share on other sites More sharing options...
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