So when I bought the Caddy, I knew it had a cooling system issue. The previous owner had diagnosed it as a leaking water pump, so that’s where I started. Little did I know what lay in store for me!

First, the 429 Cadillac motor which is in the 67’ Deville was only made for about two years, and in very low volume. As such, there is hardly any aftermarket parts available for it. I spent about two weeks trying to track down a water pump before finally finding one on eBay. One of the biggest issues was that I could not tell if the pump was a one, or two inlet pump. None of the illustrations showed any difference between the two. I finally was able to track down a Cardone part number, and find actual photographs of the parts. Turns out I had a one inlet pump.

So secure in knowing that I’d ordered the right water pump, and a number of other supporting parts (thermostat, hoses, belts, gaskets, etc), I started tearing things down. The first thing I noticed is that the apparent leak in the cooling system probably wasn’t originating from the water pump, but looked like it was likely coming from the lower radiator hose which was bulged and clearly distressed. This is interesting, since the pump that was installed was aluminum just like the original, and could possibly be the stock water pump!

I also took this opportunity to remove some other ancillary bits which weren’t needed or functional. Someone before me had already disabled the “smog pump” system by removing the hoses from the air pump to the inlets on the exhaust manifold, but they had left the smog pump and brackets in place, so I finished the job of removing those. I also removed the A/C compressor since that system had long since lost pressure and was not operational. Interestingly, the compressor was only held on by a single bolt!!

I noticed also that the mechanical fan attached to the water pump did not have a clutch, which is normally installed on the A/C equipped cars. I decided that rather than trying to reuse that fan, I’d go ahead and install an electric fan, we’ll elaborate more on that in a later post though. The radiator also seemed fairly new. Nicely painted, no bent fins and no obvious rust inside like there obviously was in the block.

One other thing I noted was that the harmonic balancer on the crank appears damaged. It kinda looks like someone took a big hammer and hit it, causing it to bend into a sort of taco shape. Going to need to probably pull that off and see what’s what.

So, having completed the water pump R&R and getting it all back together, I started the car up to pull it into the driveway and let it warm up before topping off the cooling system. I cleaned up a bit as it idled in the driveway, then went to “tap” the throttle to bring it off of high idle. Of course, the throttle stuck! After getting the pedal to come back up, the engine was still running, and all seemed well aside from a little smoke. Then, I started to notice a “clunking” sound that was coming from the passenger side of the engine compartment. Not really consistent, and didn’t increase or decrease with engine speed. Not knowing what it was, I quickly pulled the car back into the garage, and called it quits.

And that is how it has sat for several days since then. I haven’t had a chance to look into the mystery clunking noise, and the balancer is still misshapen. I had hoped to get some miles out of the stock 429 before doing an engine swap (which was always my plan), but it’s starting to look less promising that I’ll be able to do that. A shame too since I wanted to try to get a chassis dyno run or two in order to see the “actual” stock horsepower/torque numbers of the 429.

I’ll do a bit more diagnosis of the “clunking” noise, and see if I can repair the balancer without too much cost. Stay tuned here for more!