928 Radiator Replacement
1981 928

On Sept 30, 1999 while waiting at a stop light at Shattuck and Dwight Way in Berkeley the engine died. I tried to restart the engine, the starter worked, but the engine would not engage. Not wanting to run down the battery, I got out and pushed the car into a nearby parking space (very rare in Berkeley). I noticed a stream of coolant coming out of the engine compartment. I looked back down the street and noticed it had only started about 10 feet back. I opened the hood and saw coolant pouring out of the bottom of the radiator (the aluminum part). The temperature gauge was still sitting at the usual 2/3rds position.

Anyway, I got the car towed home. After returning from my China vacation, I ordered a new DEVEK radiator. It was out of stock so they had to order one. I got the radiator Thursday (11/18), and installed it this weekend.

I had already pulled off the bottom engine cover (6 10mm Hex screws), bottom fan cover (2 phillips screws), top fan cover 2 nylon ties (should be 2 screws), and both air intack tubes. This took about 20 miniutes.

As most of the coolant had already drained from the radiator, I disconnected the 3 radiator hoses (all had screw on hose clamps). For the transmission cooler lines I had to get a new 12" adjustable wrench as my 10" one couldn't open to 1 1/4". After my first attempt to loosen the top fitting I decided to spray them both with WD40 and wait. After 10 minutes I tried again, and was able to loosen the nut (only lost a little bit of skin on the back of the radiator). I had placed a drain pan under the radiator to catch the transmission fluid. Not much came out of the top hose. I got under the car and disconnected the bottom fitting. It was a lot easier (more room, no injuries). There was about 6-10 oz. of transmission fluid that ran out.

I then removed the two top radiator mounts (13mm hex bolt). As I raised the radiator from the engine bay I disconnected the wires attached to the temperature sensor, then lifted it the rest of the way out.

Next I cleaned out all the junk that had been trapped between the radiator and a/c condensor (leaves, cigarette butts, packing peanuts) and reinstalled the bottom radiator mounts which had fallen out.

I then crawled back under the car and drained the coolant from the engine block (2 13mm bolts on the each side of the engine (passenger side , drivers side) near the back where the exhaust pipe connects to the cataylic converter). This isn't required, and will add lots of time when it comes time to add the coolant, but I figured I'll replace all the coolant at this time. It's recommended that you replace the washers when you drain the fluid.

The new radiator came with some copper washers and 2 new hose clamps, but I had to salvage the transmission cooler fittings and temperature sensor off the old radiator. DEVEK provides instructions on installing them on the new radiator (3 washers per cooler fitting...).

Now it was time to put in the new radiator. Making sure all the hoses were out of the way I lowered it into the engine bay (DEVEK recommends that you replace the upper and lower radiator hoses at this time). The most difficult part of the whole operation was connecting the wires onto the temperator sensor. There's not a lot of room to get your hands in there, the wire leads are very short, and the rubber cover keeps getting in the way.

After connecting the transmission cooler hoses and radiator hoses (using the new hose clamps that came with the radiator), I installed the top radiator mounts and clips to hold the small hose that goes to the coolant tank. The bottom fan cover mounts were different on the new radiator, it was easier to attach and cleaner to look at. The top fan cover just slipped into place and I used nylons ties to attach it (as per prior installation). I then installed the air intake hoses, making sure to connect the bottoms to the timing belt cover.

After talking to Susan at DEVEK it was time to fill the radiator. The radiator cap is not on the radiator, but on an expansion tank at the rear of the engine bay on the passnger side next to the window washing fluid fill cap (installed 11/12/99, cost $2.50, no web page). I placed the heater slide to maximum heat, to allow coolant to flow into the heater core. I used a total of 1 3/4 gallons of Prestone anti-freeze, 2+ gallons of distilled water, and one bottle of Red Line Water Wettener. I filled the tank slowly using a small funnel, allowing the coolant to flow into the engine and radiator. It took about 35 minutes before the coolant level stopped lowering.

Next I crawled under the car and added less then a pint of Transmission fluid. The fill spout is on the back of the transmission on the passenger side. I used a small hand pump I had bought at Kragens for $5. I also looked for any leaks at the radiator connections.

With the radiator cap off, I started the car (still raised) and ran the engine for a couple of minutes. I check the coolant level again and it had gone down, so I added more coolant. I repeated this step several times until the coolant stopped changing. I also checked the transmission fluid level and for connection leaks. [Side Note: I was kind of amazed that it started. The car had been sitting in the garage for almost 2 months, I had changed the vacuum lines, air throttle gasket, air filter, fuel filter, spark plugs, wires, distributor, rotor, and radiator/transmission cooler. I had also found a broken oxygen sensor (replace 1/9/00), loose vacuum line to the tranmission (replaced 3/22/00) and a missing engine cover ( replaced 12/4/99).]

I lowered the car off the jack stands and took the car for a quick test drive. Around the block a few times (no problem), on the freeway (no problem), and back home (no problem :). I parked the car for the night, placing newspaper under the radiator, transmission, and fuel filter to find any leaks. So far, so good.

The total cost of the radiator change was about $700 and actual work time was about 4 hours (lots more looking around, cleaning, and wonder what is that for). Anyone want an old broken 928 radiator?

After a few days I noticed transmission fluid leaking from the bottom transmission cooler line. The fluid only came out when the engine was running. I tried tightening the fittings, but that didn't stop the problem. I ordered a new hose ($40) and installed it the next weekend. I lost a little more transmission fluid when I disconnected the hose, so I had to repeat the adding transmission fluid process. It had been leaking fluid from the passenger side front before the radiator change, but I wasn't sure where it was coming from. Now the leak has stopped.

Before Pictures:

Back side of the radiator with fan covers removed

After Pictures:

Back side of the DEVEK radiator with fan covers removed (Ohhh, Ahhh)

Engine bay after the fan covers and air intake hoses reinstalled

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Copyright 1999, George A Suennen
written: 11/22/99
rev: 06/16/00