Need help on water pump for 85 Eldorado with 4100

[pacecar76]

I need to replace the water pump on my 85 Eldorado with 4100 engine. My mechanic has now tried 3, including a new AC Delco, but says all 3 are a slightly different size than the original (the car has 28K miles, so I believe the water pump is the original one) and will not fit.
We are trying to get the old one re-manufactured, but does anyone have insight on this? Why would the original be slightly different?
Thank you!
Alan Oldfield
#28933

[James Landi]

Over the course of 25 years, I have owned four Cadillacs with 4100 engines... I have had the radiators and water pumps replaced on all of these cars.  Most recently, (past five years), I have not been able to find the original radiator... only aluminum substitutes are available... but never had an issue with water pumps not fitting.  The "remanufactured" pumps simply have new bearings and seals--- what could possibly be the problem for your car?   ALso, I must add here, given my extensive experience with the 4100 engine... USE ONLY THE GM coolant additive DO NOT USE STOP LEAK!... also, go the extra dollars for a new radiator...    James Landi

[TJ Hopland]

What sort of difference?   Like way different so no way its the correct part or they look the same till he actually goes to bolt it up and that is when he sees the issue?   I'm just wondering if he is getting the one for the transverse engines that came out that year?  Those are a lot different, the 'pump' section hangs off the side of the engine and there is then a big giant wing with what seems like 1000 bolts to the front of the engine.   Maybe have him look up an 83 so there is no chance of getting the transverse one?   Only other engine option for 85 was the Olds diesel.   The olds one is similar to the Cadillac except its got a pipe nipple top center that went to the T stat housing. 

[Whit Otis, 1188]

I bought a replacement upgrade (lifetime warranty) water pump for my 85 HT4100.  It was identical to the original and bolted right on.  If you do it yourself, be sure to follow the factory manual torque specs as there are about 3 or 4 different size bolts/nuts to be torqued and it needs to be done in the proper sequence.

Whit

PS While you're in there, don't forget to clean and wax the fan blade, power steering pump pulley and clean up the plastic fan shroud and whatever else.

[pacecar76]

Thanks Whit!
Can you recall where you got the pump or any information to help me find the same one?
Alan

[Whit Otis, 1188]

Alan,
I got my pump at NAPA.  It was brand new, not a remanufactured unit.  The part number is 44028.  Product line was TFW.  List price was $106.25.... I got mine for $60.25 not including tax.  Also, you may want to change out your thermostat while you have all the hoses, etc. off.   If you do that, then you will need to pick up a therostat housing gasket.  You will also need to pick up an o ring to seal the tube that goes between the water pump and thermostat housing.  I think one of them came with the water pump, but it takes two of them.  If you go to NAPA, check with them and see what comes with the pump.  Don't forget to pick up the "pills" that you need to put into the system after you have drained, flushed and changed out the water pump.  You can buy the Delco product from a GM dealer or Bars Leak from NAPA, P/N HDC.  They are identical as Bars Leak makes them for GM.  Search for thread on this forum re this.  Call or email if questions

Whit

[pacecar76]

Thank you!

Alan