Radiator replacement

I replaced my Monte Carlo’s radiator today. The job wasn’t as bad as I thought it would be.

This leak started a couple of weeks before Thanksgiving. Before realizing it was an unfixable leak where the plastic side tanks met the metal center part of the radiator, I ran a can of stop leak in the system in a futile effort to make it last longer. It didn’t work, and it lately got to the point where I was refilling the reservoir every other day.

I had to do this today (Saturday, Dec. 8) because the weather is turning cold and rainy tomorrow (Sunday, Dec. 9).

Here’s how I started out:

45 minutes later, it’s out. Here’s the condenser:

The old radiator and the new one on the box:

I had to take some clips and parts off the old one and put it in the new one. One of the parts was the coolant level sensor. It was full of “mud”:

This “mud” is apparently common in systems running GM’s orange Dexcool coolant. As an aside, this coolant is commonly blamed for many problems. My gut feeling is that Dexcool’s faults are badly overblown, and at worst, may be responsible for a small increase in problems only with certain vehicles–such as 3.1L engines eating intake manifold gaskets (part 1, part 2)!

The new radiator is installed, and all parts are back in place:

I saw this notch in the radiator:

It turns out it only dug into the fins, not the tubes, and the old radiator had it, too. I guess it allows the radiator to flex laterally? While aluminum allows for far more efficient radiator design, it is more rigid and less bend-tolerant than older brass radiators.

Refilling the radiator in these cars involves opening some bleeder screws in the engine. I think it is this way because, due to the aerodynamic shape of the front of the car, the top of the radiator is well below the intake manifold. Therefore, you have to open the bleeders while filling and again while the engine is running to let air bubbles escape. Otherwise, the thermostat may take a while to open.

The car is back together, and the leak is gone!

One thought on “Radiator replacement”

  1. Yea the bleed screws are because the radiators top is lower then the engine “top”.

    The Porsche 944s were that way also but had a much weirder way of bleeding air out of the system

    My Girlfriends 96 Olds Cutlass Supreme has this same engine and we are having coolant problems it seems that I have to refill the tank every month or so.

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