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2000 SLS severe overheating w/new radiator install. Put original back and it's fine.

445 Views 8 Replies 4 Participants Last post by  sefiro
Original radiator in my 2000 Seville has a small leak where the pin on the top of the right radiator tank broke off. Bought a new radiator off ebay, installed it and filled it with coolant (via the overflow tank, of course). Ran it at idle until the thermostat opened and put more in until it was full. Drove it and within about a mile or so it got warmer than usual so I turned around and by the time I got home the temp gauge was past 2 o'clock with the "engine hot" warning flashing. Parked it for a while hoping the cooling down process would help with purging and added more coolant and drove it again with the same result. I removed the new radiator and put the original back in and after the refill with a heat up and cool down and another top off it ran normal (needle at 12 o'clock). I ran water from my hose into the new radiator's openings and it came out the opposite one seemingly just fine. I should point out in was a very inexpensive part (about $70 shipped) from a company called Sunbelt Radiators (Here's the link:, but if the water flows through it shouldn't that be what really matters as far as just the cooling aspect? The car has over 185,000 miles so I don't want to spend any more than is necessary since it's a pretty tired looking and driving vehicle and a second car. I checked local yards for a used one but all they have are post-2000 models which aren't compatible. Any ideas, advice, or suggestions? Anyone buy one of these radiators?
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How fast did it flow?
Just as fast as it went in. Took a few seconds before it came out the other outlet, of course, but flowed just as heavy as the hose was producing. Quite the opposite of what I was expecting. I figured it had some defect that would be restricting flow, maybe to the point where it would back up and start coming out where I was putting it in, but it was pouring right out of the other end no problem.
Probably constructed with larger than spec pipes which doesn't provide surface area or constriction to enable heat to move to fins for dispetsion.
Never thought of that. Thanks.
Sometimes getting all the air out of the system takes a little time. If you where running hot, you most likely still had air in the system. Top it off til it's at the proper level and take it for a short ride. Top oof again as needed. On one occasion I had to top mine of 3 or 4 times until it stabilized.
I reinstalled it and it took four warm up-cool down top off cycles and it's running at the normal temperature now. I guess since the original one would return to normal temps almost immediately each of the times I removed-replaced it for the two previous repairs (alternator and ac compressor) I was expecting the same with the new one. Thanks to all for your advice and input. I really appreciate it.
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