Radiator reservoir leak and delaying the inevitable

chado

New member
Hey all, hoping for a bit of mechanical wisdom. I have a 2002 with 250k miles on it. I’m pretty sure the reservoir has been leaking the whole time I’ve owned it, but has possibly gotten worse over time. I tried to patch with JB putty, but like others around here, the leak persisted.

The leak, however, seems to be on the upper part of the reservoir. When I fill it to the max line, it leaks out like an inch of fluid within a few days, but then it leaks very little after that. My engine temperature once I get going is always just above 180. I’ve never been close to over heating as far as I know.

I have a few questions:

1. Is it alright if the coolant reservoir isn’t filled to the max line if the coolant light isn’t coming on?

2. Is it safe to be drive the van with a loose radiator cap (that is, it goes on with 2 turns, I just turn it once), which is what I’ve been doing, at the suggestion of another thread.

3. Could the loosened radiator cap possibly be making it where I can’t accelerate as quickly (which seems to be happening when I’m getting on the highway)

4. How urgently should I be trying to replace my radiator? For the time being I am just driving it sporadically around town a bit, but later this summer I’ll be taking it on a long road trip... is it bad idea to delay the new radiator even if I keep an eye on the engine temp?

Thanks for help!
 

trc.rhubarb

Well-known member
When mine did that, i had two leaks. One was a pinhole where the plastic met the metal.
The other was from the water pump.
having just done the entire cooling system replacement (pump, pulleys, hoses, radiator, electric pump, fan...) it was very easy and took just a couple of hours total.

With the cap loose, you boil over at 212f or less and risk overheating once summer comes.
 

220629

Well-known member
A loose cap can be a stop gap measure. Less pressure inside the system = less loss of coolant.

I don't believe there is any short term issue with running a loose cap. Over the long term it may increase the chances of local turbulence, cavitation, and possibly erosion.

What is long term? :idunno:

My guess is that up to 500 miles would easily be short term. I have no data.

:2cents: vic
 

Cheyenne

UK 2004 T1N 313CDi
Question: Does your low coolant warning light actually work? If you don't know then test it now before it's too late! Turn the sensor a quarter of a turn then very slowly lift it out of the header tank while an assistant watches the light with the ignition turned ON. Be careful as once the sensor is removed fully from its location the light will be off. The other way to test is by passing a magnet over the tip of the sensor, again while an assistant watches the light.

Driving with the cap is bad practice as explained above and can lead to local boiling in the cylinder head and possible later engine damage. Get the radiator replaced asap! A radiator is cheap when compared to the cost of a replacement engine!!! Oh and DO NOT buy a cheap Chinese knock off, Dennis has posted previously which brands are OK and which to avoid.

I am not aware of any correlation between a low coolant level and/or loosened pressure cap and loss of engine power. This is more likely a boost problem and seen as you have a 2002 with the vacuum operated turbo boost control that is where I would start looking for problems. Have you had your Sprinter scanned for Sprinter specific codes? A 'run of the mill' parts store OBD scanner is unlikely to give you true codes in this instance.

Keith.
 
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ECU

2006 T1n 118 Sprinter
I've noticed the increase in radiator complaints on the list in the last two years. As if they fail after a certain age when the plastic deteriorates.
Or else, I noticed this because I replaced my leaking radiator about two years ago.
 

220629

Well-known member
I've noticed the increase in radiator complaints on the list in the last two years. As if they fail after a certain age when the plastic deteriorates.
Or else, I noticed this because I replaced my leaking radiator about two years ago.
:idunno:

Service miles and service age do take their toll. It would be interesting to know if the cracks happen in the same area eg. - turbo resonator failures. Perhaps some epoxy applied before failure would add enough strength to avoid the failure.

I recall that Steve Ball has swapped end tanks over from one radiator to another.
http://www.mercedes.gen.in/post-index/

If the owner was willing to remove the tank(s) from a spare used radiator, it would be easier to ship parts vs the complete unit.

:2cents: vvic
 

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