Vulture

Hi vulture,

you,re welcome... My gmc has now completed nearly two years running since sorting out the radiator/block.

I will change the anti-freeze before our first run-out to york in april as it will have been in the engine for about two years, the inside of the radiator ( that i can see ) is still as clean as the day it was re-fitted.by the way, i remember seeing your truck at hunmanby a few years ago. From memory it looks a lot better now than when i saw it , i think it had been standing for a long time and looked a bit rough. Nice to see it back on the road and to know it's gone to a good home. Best wishes steve.

Steve

Had planned to spend an hour or so on the truck today, but pressure or work and my boy being laid up with some lousy vomiting bug he picked up from school scuppered my plans sadly.... Not sure if I'll get time tomorrow to doing anything, plus the weather forecast for this part of the country is heavy rain .

If I can I'll drop by Rex Ward on Friday and pick up a bottom hose on my way home, and have a go at the truck at the weekend.

Yes, it looked a bit tired and unloved when I first picked it up at Hunmanby with its six different shades of grey, but a bit of TLC, a repaint, six new tyres, new canvas doors and cab canvas and its looking quite a bit smarter. The seats are really really tired so I'm getting some new ones made by Allied Forces, which I pick up middle of next month. Main expenditure after that will be me new canvas for the cargo body, but I'm pretty much out of funds now, so I'll have to save up for a bit for that ! LOL Lots of servicing projects I want to potter on with. Can't wait for the better weather and longer days to come back

Kind regards

Ian

and then I can start to think about how I am going to tell my better half that we may be receiving a new house guest!

I you have that much free rust in your cooling system then whats in the radiator tubes? The cylinder jacket?

 

For the gentlemen that are dismissing a dirty cooling system, or WORSE, saying its NORMAL please stop, stop right now.

 

Its obvious that at some point the coolant was simply water, or the antifreeze was so old that its lost its properties and allowed the cast iron to rust. The rust is turns to sediment which clogs the passages in the block and radiator tubes.

 

If you think its normal, then you really need to read up on PROPER coolant maintenance. My 42 GPW, 43 GMC and 66 M35A2's innards look like the day they were cast.

 

A proper flush (nothing you buy off the shelf at a store is worth anything.. you need professional chemicals and a air agitation system) is needed. Your innards should look like cast iron (grayish).

 

You may go another month, year, or decade with the condition its in now.. there is no way to tell. But you hare having cooling issues now, might as well fix it and be done with it. Not sure what it costs to tow a CCKW in the UK, but I've talked to several heavy tow tuck company's in the area (I work in distribution, so having a tow driver on the yard is not an uncommon occurrence) and none of them would even start up the wrecker for less than $500, plus mileage (Approx $15 per mile... BOTH WAYS for a 15,000 lb cckw).

 

So a few quid for a flush, pressure check and refill is the cheaper of the two options, in my book.

I'm taking my car the local garage for some work tomorrow' I'll see what they have to hand. I could always opt for Bars Flush Cooling System Cleaner from my local Halfords, although from what you say, a harsher clean might be a better long-term solution. A grey cast iron look to the insides, is certainly something to aspire to.

I'm with a recovery company called Flux Recovery. For the annual sum of £32 they provide home start and road-side assistance and recovery on the truck. Admittedly there is a £3,000 limit on the costs they will swallow in a year, but that is a lot of recovery activity ! :-) Given that I've already been recovered once this year when an oil pipe failed, I've already had value for money !

Kind regards

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

Journeyman

:thanx:for your thoughts, much appreciated . Good to have a clear steer on the gasket question

Wow ! Best of luck with that, what a great vehicle

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 :-)

I do think this is how the original rad caps are made, without any kind of gasket except for the brass / copper flange part of the rad cap which sits on the top lip of the rad filler cap hole. This is how mine is and had no problems with using water or over heating over the past 15 years of long trips at 40 ish MPH, dual carriageways ect. to France and loaded.

Also regarding the filling of the rad, there is a baffle over the top hose inlet to the rad so you cant see the water level through the filler cap, all I do is top it up till you can see it then put cap on and use it, excess water is then pushed out through the overflow and then it stops once its at the correct level. Check every now and then and that's about it.

Hi Cubed

The penny has dropped for me, after a posting on the other thread. The gasket sits in the neck of the rad, not on the cap it self, which is why of course I couldn't see anything (chuckle). :blush: :n00b:

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

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.

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

There are many and varied imponderables with the cooling system, anything from a blown gasket to an external leak.

I think that the first thing to establish might be that you have not got a blown head gasket. If the radiator is filled to the top and you allow the engine to tick over for several minutes, and you dont suffer a great eruption of water from the rad all at regular intervals, then you can assume that the gasket is o.k. You could be suffering from a blocked rad, the fan belt may be loose, or a defective cap, but one thing is for sure, you certainly dont need an expansion tank in this country.

Good luck and may your troubles be minor.

Big Ray

I've did the tick over check for blown headgasket, a month or so back, when I started to become suspicious of something amiss... Nothing too see. As for my troubles being minor, time will tell...

Yeah but he needs to know that if he gets a new cap, it needs to have the fibre gasket otherwise its not going to seal even with a new cap.

Deadline

Looking at the existing cap I can't see any gasket... I'll post a photo on the Temperament gauge puzzle thread

Further to my last post I think we should now wait for Vulture's report on the vehicle after he has fitted the new thermostat and then deal with any other eventualities if and when they occur. I now await Vulture's report with interest.

Degsy, brace yourself ! One will be appearing on the Temperament gauge puzzle thread very shortly (just need to upload some photos)

Well he want through Sandhurst and was a Captain, and a Major in the TA after the war. It always amazes me how young the officers were as he was not long out of school and had only just started working as a clark at the Blue Funnel Line (Alfred Hold) in Liverpool.He spent the rest of his life after the war partially deaf and with permanent tinnitus due to noise of the gun in his tank. I don't really remember many of his stories but he became fluent in Italian and married an Italian Contessa. Sadly I never met her as he was onto his third wife before I emerged! I do remember that he remains convinced that he owes his life to the lack of a power traverse on the Tiger tank. They happened upon one in a town and he got two shots at it, both hits, the first an HE (always kept an HE up the spout) and a second AP, both of which bounced off the Tiger's armour. During this time the Tigers gun was slowly traversing in their direction, but its slow movement allowed them just enough time to back up out of the way! A hit from the Tigers (88mm?) gun would surely have killed the Sherman and its crew.Julian.

Hi Ian,

 

Can I politely ask why you are looking into this? Is there a problem with the truck?

 

Regards - Mike

Mike

I hesitate to answer for the fear of bringing the wrath of the purists down upon me, but there are three reasons:

1. I've had bad experinces in the past with coolant levels when I was running some of my older cars.

2. I find it very annoying that I can't check the collant level without having to top-up. In doing so of course you end up wasting anti-freeze solution when it blows it out, plus you can't monitor it journey to journey, if you have a problem.

3. I do have some concerns with the truck, although these might be explained by the Thermostat playing up over these last months, and now stopping working all together.

Kind regards

Ian

Gordon and Deadline

Thanks for that info, great stuff. Next time I'm talking to Rex Ward I'll ask him if he has the right bits in stock

Kind regards

Ian

I know the purist may be offended by the suggestion (so if you are please don't reply), but does anyone have, heard of, or seen a (presumably post war) mod to a CCKW to fit a radiator expansion tank bottle ?

Kind regards

Ian

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

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

Hi guys

 

I've long since felt that their is a huge void West of us and East of East Midlands area, so best of luck and any help Suffolk Area can give, then don't hesitate to ask!

 

All the best

 

Clive - Former Suffolk Area Secretary and now holding the Area purse strings!

Thanks for that Clive

Yes this was a good first meeting . Including myself there were 26 attendees with (as you would expect) a broad ownership spectrum ranging from not owning any vehicle, up to having about 8. For the moment we are going to continue meeting in the Montague Club in Huntingdon, every 2nd Thursday of the month at 20:00. We worked our way through the sample MVT Area constitution, appointed a Deputy Area Sec, agreed to use a Yahoo Group to disseminate info (and files) and amongst other things agreed to try and have a 'Spring Run' sometime in the Easter break. All went well, already looking forward to next months meeting

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

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

Guys, thanks for your thoughts :-). Lots of good ideas :idea: on how to try and tackle this puzzle. Weather permitting I'm going to fire the old girl up in the morning. I'll block off half the radiator with cardboard and see how things go. Excuse the NOOB question :n00b: but I'm assuming I block the front of the rad off ? (i.e. not the side with the fan). I think a call into Rex Ward to get a spare thermostat is also required tommorrrow.

I'm curious as to how many people get their engine up to working temperature before driving off. I know the manual says to do so, but I thought that the 'modern' thinking was get vehicles up to working temp as quick as possible (by driving them) but not to work the engine too hard in the process.

Kind regards to all

Ian

It was a beautiful winters day here yesterday, so I cranked up the truck and used it for the school run to pick my lad up, a 12 mile round trip. Its pretty cold, about 5 degrees, so I'm expecting it will take a while to get up to operating temp, but the temp gauge stays stubbornly unmoved throughout the entire journey. On getting back straightaway I'm out crawling over the engine and checking the manual. I can't find anything wrong, i.e. no leaks from the tube. I look back in the cab and notice then that with the engine off that temperature is now showing on the gauge. I then start the truck up, and immediately the temperate falls back to bottom. On stopping the engine, it rises again ! I wondered if there was an issue with the water-coolant level, but 1.5 litres of water and anti-freeze brought it up to the rim.

Any ideas guys ?

Kind regards to all

Ian