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Rad cap and misc coolant hose replacement project

630 views 6 replies 4 participants last post by  snik 
#1 ·
Hello folks,

So this summer, I am planning on changing a few coolant pieces as preventive maintenance. My coupe has always had a coolant drain/refill every 2 yrs (Zerex G05/distilled water), so the hoses are in good shape (nothing swollen).

Ordered all parts below from the dealer:

• Rear T is already done
• The short 90 degree water pump hose in the front has already been done
• The short straight hose right behind the water pump hasn't been done, but it looks ok/not swollen. Is that an easy replacement or does the whole water pump assembly need to be removed for this?
• Front T has been ordered and it's here
• The 2 cyl head to firewall hoses have been ordered and they are here as well (thanks to Mava for flagging this in one of his posts)
• New rad drain cock is here as well
• Upper/lower rad hoses are in really good shape and I am thinking of leaving them as-is. OEM is about $60~$80 a piece, but ACDelco ones are under $20. Are these hoses known to fail?
• “Reservoir to radiator” hose has been ordered and it's here
• Reservoir: I have the old style reservoir w/ a metal cap. I ordered the new style reservoir with a screw-on plastic rad cap. When it arrived, the rad cap wasn't included (dealer never told me) so I ordered it separately and had to wait another few days. The new rad cap has now arrived and it’s the old metal style cap. When the dealer looks up the part # by VIN, the metal one keeps coming up, and it does not say "superseded by ... new part #" .. anyway, they are looking into it, and will try to track the appropriate rad cap.

I just thought it was funny that a) when ordering the reservoir, it does not come with a cap, and b) VIN search for the reservoir brings up the new style reservoir but the old style rad cap.

I will post some pics in a week or two when I get to replace everything.

Next summer I will buy high quality silicon coolant hoses and will tackle the windshield heater hoses, and all the remaining small hoses in and out of the duo valve.
 
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#2 ·
Upper/lower rad hoses are in really good shape and I am thinking of leaving them as-is. OEM is about $60~$80 a piece, but ACDelco ones are under $20. Are these hoses known to fail?
i was told by a mechanic with a lot of experience in these cars that coolant hoses on w140 are not a problem at all. he believes that they can last several decades.
 
#4 ·
While I would not disagree about the longevity of MB coolant hose(s) less the plastic Tees, I would also add...it would be a shame to overheat, break down and possible ruin an engine for the cost and easy labor of hose replacements. What exactly would be going through you head as you sit on the side of the road something like....."22.4 year old rubber hoses under heat and pressure cycling what was I thinking?"

Seems a no brainer

Seth
 
#5 ·
While I would not disagree about the longevity of MB coolant hose(s) less the plastic Tees, I would also add...it would be a shame to overheat, break down and possible ruin an engine for the cost and easy labor of hose replacements. What exactly would be going through you head as you sit on the side of the road something like....."22.4 year old rubber hoses under heat and pressure cycling what was I thinking?"
we probably all agree that every component in our cars should be replaced to increase reliability of our cars. however in practice this does not make any sense (i.e., it is too expensive). even wheels do probably have some microscopic cracks ... material gets tired after so many years and bumps on the road. it is mechanical engineering, not my imagination. and broken wheel is even more dangerous than broken hose. so i certainly understand you and support your main idea, but hand on my heart, my approach is different = i only replace bad things, not things which may go bad. btw, i did replace both upper and lower radiator hose when they were 22 years old and they were like new to me.
 
#7 ·
update:

Replaced above hoses today. Pretty straight forward. I was expecting the rear 2 hoses (block to firewall) to be challenging, but level of difficulty was on par with replacement of the rear T fitting. Overall straight forward.

I did the pair of windshield fluid heater hoses too .. used generic hoses as OEMs were back-ordered. My learning lessons and notes:

* The 2 hoses are not the same size .. although they look the same, inside diameters are different
* Process was much easier when I removed the right headlight
* Also, I pulled the heater element and removed the clamps and installed the new hoses/clamps on the bench, then installed the assembly back inside the washer reservoir

The only non OEM parts I used were "Gates" upper and lower rad hoses. My observations:

* The obvious difference was the short rigid plastic shield that's on the OEM hoses seems to be missing from the aftermarket brand
* On the lower hoses, the shield is intended to serve as a barrier between the alternator bolt and the hose (they are in very close proximity)
* In the upper hose, there is a section where the hose almost rubs against the PS hose and the OEM hose has a shield around the area
* Tightening the lower hose was a bit of a pain (not the rad side, the end that connects to the engine).

The only hoses remaining now are:

* All Duovalve hoses
* The straight/short hose that goes from the block to the upper thermostat housing - looks like there are 3 bolts on the upper thermostat assembly, and if I remove them, replacing that short hose should be a breeze. Question: Is there a gasket or O ring under the upper t-housing assembly? Just like to know what to expect when I remove those 3 bolts.
 
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