Midwestdrifter
Engineer In Residence
From the chem I weld manual.
Coolant usage and pressure in system.
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owner
Oz '03 316CDI LWB ex-Ambo Patient Transport
The instructions are very clear that you must add it only with the entire radiator (and system) full of straight water. You fill with water, run till hot with cap off, refill to top as necessary, then drain just enough to fit the guff in.
It particularly mentions the water must cover all the radiator channels before adding the guff. So my guess is the guff reacts with combustion gasses/air in the system, rather than reacting to small passages. If it just reacted to small passages it would immediately clog your radiator.
owner
Oz '03 316CDI LWB ex-Ambo Patient Transport
I usually check for cold pressure every month or two to see if the chem-i-weld repair has failed. The system has been fine now for 10,000km and well over a year (and a citric acid flush at the start). But...
I suddenly had a pressurised cooling system again recently. This was after a long high-speed run in 39DegC ambient conditions, where the coolant temps exceeded 94DegC for about 5-10mins of a 12 hour trip.
I have since been checking for cold pressure more often. I have not had a repeat of this incident, but I have also not seen temps of 94DegC. The closest I got was 91DegC for a few minutes. I have done several long high speed runs since, just not above 91DegC.
So my theory is that the chem-i-weld repair is fully sealed when temps are below 94DegC. But beyond that the failure opens up with thermal expansion and causes pressurisation. When I did the chem-i-weld repair it says to run the engine at higher than normal temps while adding the guff. I achieved this by partially blocking the radiator with cardboard. IIRC I only went to about 94DegC with the chem-i-weld in the system.
This would explain why the crack opens up above this temp.
So I am happy to keep running with the original chem-i-weld repair for now. I only see 94DegC on very hot days and high loads, so maybe once or twice a year if that. Now that I know it opens up at this point, I will do all I can to avoid hitting 94DegC.
Next time I do chem-i-weld I will try to get the temps up a bit higher when the repair is taking place.
I suddenly had a pressurised cooling system again recently. This was after a long high-speed run in 39DegC ambient conditions, where the coolant temps exceeded 94DegC for about 5-10mins of a 12 hour trip.
I have since been checking for cold pressure more often. I have not had a repeat of this incident, but I have also not seen temps of 94DegC. The closest I got was 91DegC for a few minutes. I have done several long high speed runs since, just not above 91DegC.
So my theory is that the chem-i-weld repair is fully sealed when temps are below 94DegC. But beyond that the failure opens up with thermal expansion and causes pressurisation. When I did the chem-i-weld repair it says to run the engine at higher than normal temps while adding the guff. I achieved this by partially blocking the radiator with cardboard. IIRC I only went to about 94DegC with the chem-i-weld in the system.
This would explain why the crack opens up above this temp.
So I am happy to keep running with the original chem-i-weld repair for now. I only see 94DegC on very hot days and high loads, so maybe once or twice a year if that. Now that I know it opens up at this point, I will do all I can to avoid hitting 94DegC.
Next time I do chem-i-weld I will try to get the temps up a bit higher when the repair is taking place.
owner
Oz '03 316CDI LWB ex-Ambo Patient Transport
This year I have noticed the pressure buildup has slowly returned. It started doing it on hot days, and now its doing it all days. In fact now when I run without the cap on I get foam forming at the filler even at idle.
So I've busted out another $10 bottle of chem-i-weld today, now at 450000km.
This time I was more careful about the application process. I did it by the book. Adding the guff to the open sysyem at 96DegC and doing a few full power runs against the TC. Thats what the instructions say, just add it at higher than normal (86DegC) temp with cap off, but not boiling. Then it says to put cap on and leave it in and drive like normal until symptoms stop.
So then I also put the cap back on and ran her up to 116DegC (240F!). And I did a few more full load runs against the TC at that temp. The idea was to get the crack/leak nice and opened/expanded for the guff to get right in and seal. I will leave it in for a week and check again to see if it has worked again.
Last time I didnt really take it up to high temps when it was fresh in the system. Even during the 2 weeks i left it in I only took her to low 90's. I also did a citric acid flush on the last repair. Im pretty happy with how long the last repair lasted given the above. So fingers crossed for an even better result this time.
So I've busted out another $10 bottle of chem-i-weld today, now at 450000km.
This time I was more careful about the application process. I did it by the book. Adding the guff to the open sysyem at 96DegC and doing a few full power runs against the TC. Thats what the instructions say, just add it at higher than normal (86DegC) temp with cap off, but not boiling. Then it says to put cap on and leave it in and drive like normal until symptoms stop.
So then I also put the cap back on and ran her up to 116DegC (240F!). And I did a few more full load runs against the TC at that temp. The idea was to get the crack/leak nice and opened/expanded for the guff to get right in and seal. I will leave it in for a week and check again to see if it has worked again.
Last time I didnt really take it up to high temps when it was fresh in the system. Even during the 2 weeks i left it in I only took her to low 90's. I also did a citric acid flush on the last repair. Im pretty happy with how long the last repair lasted given the above. So fingers crossed for an even better result this time.
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owner
Oz '03 316CDI LWB ex-Ambo Patient Transport
Well it worked again. I left it in for a week after that initial burst of high temp running/application. So I drained and flushed the system with the garden hose at the oil-cooler-to-block hose.
I had drained and kept the old 2 year old MB official coolant from last time. So I filtered it through an old Brita water filter jug, and refilled the Sprinter with that old coolant. I've done few decent runs since and there is no cold pressure anymore.
For exact reference this repair was done at 445,000km Nov 20 and flushed on Dec 3 2020. Lets see how long it lasts.
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Had this issue too in the end used this same stuff it didn’t work for me or if it did just for a short while. went for the head gasket repair which of course creates other issues when injector bolts snap and glow plugs break off in the head.
The problem with that stuff is it leaves a glass like substance on all your fluid hose connections and cylinder head when you take them apart for repairs down the road.
My other issue was no heat from the heater because of the pressurized cooling system. When winter comes along , depending on where you live makes life very miserable.
The problem with that stuff is it leaves a glass like substance on all your fluid hose connections and cylinder head when you take them apart for repairs down the road.
My other issue was no heat from the heater because of the pressurized cooling system. When winter comes along , depending on where you live makes life very miserable.
owner
Oz '03 316CDI LWB ex-Ambo Patient Transport
Yeah yours sounds like it was a pretty major leak. I got a few occasional bubbles I could hear whislting through the heater circuit when you gave her a big rev, but never more than that. The heater always worked.
The theory is the guff forms that glass substance when it makes contact with air/gasses inside the sysyem. So as you had a lot of gasses, you had a lot of "glass" forming in places where it wasnt needed.
The theory is the guff forms that glass substance when it makes contact with air/gasses inside the sysyem. So as you had a lot of gasses, you had a lot of "glass" forming in places where it wasnt needed.
SprinterLex
2006 T1N 3500 Long & Tall
I can't remember when the aux fan kicks in but perhaps unplugging it could help you get 'higher than normal temperatures" in combination with the cardboard trick.
owner
Oz '03 316CDI LWB ex-Ambo Patient Transport
ROW sprinters like mine dont have the aux fan feature. The aux fan is there, but its only for the AC, it isnt controled by the ECU at all, just a relay from the simple AC circuit. (We didnt get climate control like you guys either, just old skool switch controlled fixed AC).
Anyway on to the repair... Another year later and my 2nd chemiweld repair has failed again.
During this period my thermo fan clutch had failed so I was seeing much higher temps than normal. So I guess that didnt help much.
This time Im going to try a different product. Another one that doesnt require coolant flush but not K-Seal. May as well give it a go before doing another chemiweld 1 year fix.
Anyway on to the repair... Another year later and my 2nd chemiweld repair has failed again.
During this period my thermo fan clutch had failed so I was seeing much higher temps than normal. So I guess that didnt help much.
This time Im going to try a different product. Another one that doesnt require coolant flush but not K-Seal. May as well give it a go before doing another chemiweld 1 year fix.
You can monitor radiator over-pressure like this:
1. mount a plastic jug on your door mirror, where you can see it while driving.
2. run a tube from radiator overflow into the bottom of jug.
3. put some fluid in jug.
4. when driving, you note the precise engine temperature and load, when bubbles are generated.
5. once you learn the set of conditions makes the crack in head open, expelling gas and then coolant.... you can see if you can adjust your driving slow enough to not expel a lot of coolant into the jug. You can monitor if the condition is stable, or getting WORSE. This will also tell you precisely how much coolant to add back to your radiator.
6. THIS MIGHT buy you enough time to wait for the ID PARTS thanksgiving or XMas 10% sale... 10% off brand new Spanish cylinder head... at a very good price!!
1. mount a plastic jug on your door mirror, where you can see it while driving.
2. run a tube from radiator overflow into the bottom of jug.
3. put some fluid in jug.
4. when driving, you note the precise engine temperature and load, when bubbles are generated.
5. once you learn the set of conditions makes the crack in head open, expelling gas and then coolant.... you can see if you can adjust your driving slow enough to not expel a lot of coolant into the jug. You can monitor if the condition is stable, or getting WORSE. This will also tell you precisely how much coolant to add back to your radiator.
6. THIS MIGHT buy you enough time to wait for the ID PARTS thanksgiving or XMas 10% sale... 10% off brand new Spanish cylinder head... at a very good price!!
owner
Oz '03 316CDI LWB ex-Ambo Patient Transport
Another update. After the last chem-i-weld treatment finally failed, possibly not heleped by a failed fan clutch, I tried a different product.
I got sick of having to flush and use straight water with the chem-i-weld. But I was also wary of the "just add to coolant" K-seal that didnt work for me before.
So I tried this:
Rislone Liquid Copper Block Seal - 510g
www.supercheapauto.com.au
I just added half the bottle like it says to the existing coolant. But I also blanked off the radiator and ran her up to 105C like I did with the chem-i-weld. (It doesnt say to do this on the Rislone product but I did it anyway).
It sealed basically right away and has held now for 1000km. So I will keep checking and report back. This product I think you can get worldwide unlike chem-i-weld. And so much easier just adding it to the existing coolant.
I also replaced the fan clutch with one that actually works. And I put in a new water pump at the same time, as the old one started leaking at the seal. Now the temps stay sub 90C so far which was not the case with the failed fan clutch.
I got sick of having to flush and use straight water with the chem-i-weld. But I was also wary of the "just add to coolant" K-seal that didnt work for me before.
So I tried this:
Rislone Liquid Copper Block Seal - 510g
Rislone Liquid Copper Block Seal - 510g
Rislone Liquid Copper Block Seal - 510g
www.supercheapauto.com.au
I just added half the bottle like it says to the existing coolant. But I also blanked off the radiator and ran her up to 105C like I did with the chem-i-weld. (It doesnt say to do this on the Rislone product but I did it anyway).
It sealed basically right away and has held now for 1000km. So I will keep checking and report back. This product I think you can get worldwide unlike chem-i-weld. And so much easier just adding it to the existing coolant.
I also replaced the fan clutch with one that actually works. And I put in a new water pump at the same time, as the old one started leaking at the seal. Now the temps stay sub 90C so far which was not the case with the failed fan clutch.
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Hellshalfacre
2005, 2500
Hi Owner,Another update. After the last chem-i-weld treatment finally failed, possibly not heleped by a failed fan clutch, I tried a different product.
I got sick of having to flush and use straight water with the chem-i-weld. But I was also wary of the "just add to coolant" K-seal that didnt work for me before.
So I tried this:
Rislone Liquid Copper Block Seal - 510g
Rislone Liquid Copper Block Seal - 510g
Rislone Liquid Copper Block Seal - 510g
I just added half the bottle like it says to the existing coolant. But I also blanked off the radiator and ran her up to 105C like I did with the chem-i-weld. (It doesnt say to do this on the Rislone product but I did it anyway).
It sealed basically right away and has held now for 1000km. So I will keep checking and report back. This product I think you can get worldwide unlike chem-i-weld. And so much easier just adding it to the existing coolant.
I also replaced the fan clutch with one that actually works. And I put in a new water pump at the same time, as the old one started leaking at the seal. Now the temps stay sub 90C so far which was not the case with the failed fan clutch.
Which brand fan clutch did you go with? Glad the new product is working so far.
owner
Oz '03 316CDI LWB ex-Ambo Patient Transport
I just put in a secondhand fan clutch off a spare engine. MB genuine part. It kicks in super early,seems like its fully locked by 85C (which is the thermostat temp). So the van hardly goes much above that now.
But since its summer here I reckon thats better than never kicking in like the old one. I think I'd rather just wear the extra fuel consumption than run up well into the 90Cs and sonetimes low 100Cs every hillclimb regardless of how much you baby her.
But since its summer here I reckon thats better than never kicking in like the old one. I think I'd rather just wear the extra fuel consumption than run up well into the 90Cs and sonetimes low 100Cs every hillclimb regardless of how much you baby her.
jackbombay
2003 158" shc
You must have a big hill, high ambient temps and a heavy foot to get it to 116˚! I'm surprised you've had such good luck with the sealing products!
owner
Oz '03 316CDI LWB ex-Ambo Patient Transport
No that was with the radiator blanked and bursts of WOT against the stalled torque converter. Its pretty easy to get very high temps doing that.
The highest I've ever seen in real world use was 108C. That was at idle in 42C heat with a bad fan clutch. And also 108C on the freeway at 120kph in 42C heat again with the bad fan clutch. I usually back off way before those temps but those two times it wasnt practical to stop or back off.
I took it to 116C that time to try to get the crack/leak fulky expanded to get the guff right in there.
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