Richard D

Do radiators wear out?

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For the last 5 months or so for the first 45 minutes of both stop and go driving, first stop and go then 20 minutes of non stop and go then about 20 minutes of returning driving, 20 minutes of crusing at 60 then 40 minutes of stop and go the temp gauge will up about 2 segments past half way. The car is parked between 20 and 40 minutes before return trip. I have drained until fluid is clear then drained radiator, refilled with full strenghth antifreeze conditioner (I live in Miami) yet the problem returns. Have also replaced thermostat no sign of leaks. Milage is 149,000. Have also tried bypassing heater core. Thanks to all

Richard

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I am assuming it never used to show as high previously.

Sounds more like your water pump is going out. The impeller is pressed on and over time will loosen up at temperature causing the temperature to climb slightly at first. Later it will keep climbing.

On the other topic. Radiators can clog and not flow as well with time.

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Thanks for your help, I was hoping the impeller and shaft were cast as one piece. Since they built millions of these engines should not be hard to find. I hope it is something I can do, it seems like the older I get the less I can bend over fenders and such.

Regards

Richard.

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Radiators don't really wear out. Deposits build up on the inside of the tubes in the radiator that prevent good heat transfer between the coolant flowing through the radiator and the air blowing between the tubes. Instead of the heat being picked up by the cooler air, the heat is carried back to the engine by the coolant making it harder to cool the engine. Dirt can also clog the radiator fins reducing the air flow through the radiator.

 

There use to be a lot of radiator shops that would clean the radiators to make them more efficient. The price of radiators has gotten so cheap that it makes more sense to buy a new one instead of cleaning an old one.

 

Radiators and water pumps for your Reatta can be found here. Reatta Cooling System Parts

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It is not uncommon for the water temp indicator to go up one or more "ticks" (this is on 1990-1991 cars, the 88-89 gives and actual temperature)  when in traffic.

The radiator fans are programed to ramp up in stages as the coolant temperature rises.       Most Reatta owners are aware of this and either live with it or take some actions.    Note that this is more of a problem to owners living in the south where the car sees outside temperatures in the 90-100 range daily.

As the cars warms,  the ECM monitors the coolant temperature.     At specified temps, the ECM turns on different relays that then control the fans.   First you get one fan,  then two fans wired in series so they only run at 1/2 speed then the last step is 2 fans running at full speed.     What you are seeing is the upper end of the range when the 2 fans are running at 1/2 speed and if the temp goes past the preset they kick into full speed and the gage drops.

The easiest solution is to have the chip in the ECM reprogrammed to kick the fans on high at a lower coolant temperature.     Some owners have purchased aftermarket fan controllers that are adjustable,   that also works but you need to splice into the factory wiring to install the controller.

 

I am not sure what you mean by "I have drained until fluid is clear then drained radiator, refilled with full strenghth antifreeze conditioner"........ the consensus is that you should run 50/50 (distilled water/antifreeze) regardless of where you live.   The antifreeze has chemicals that lubricate the water pump and also have antirust/corrosion inhibitors in it,  that are good protection.     If you run just water,  you need to add water pump lube/inhibitor additive which seems to be harder to find in auto parts stores,   plus, do not run 100% antifreeze as it alone has a lower boiling point that when mixed with water.   Another thing to notice...many antifreeze containers are already 50/50 mixes..... which is fine but don't dilute that with water.

 

As a side note, Denny Manner a Reatta owner, and retired GM powertrain engineer that worked on this engine during his carreer at GM, says they ran these engines at 230+ for days without problems.   

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pretty much most has already been posted. to reiterate: DO NOT use 100% antifreeze!!!

 

make sure the fans are working correctly.

 

if a "flush" product such as Prestone wasn't used to loosen up deposits during your flush, you may want to do that. don't forget to have your heater on full temp and fan on high to get the product in there. and make sure all the air gets "burped" out of the system.

 

i haven't used this new product yet, but plan on trying it when i flush out my '51 soon. it's now available at most FLAPS. evapo-rust thermocure: http://www.evapo-rust.com/thermocure/

 

 

 

 

 

 

 

 

 

 

 

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Mc_Reatta came up with a harness that has factory ends. It forces the car to run both fans at high speed all the time. Before he left he gave me three of them [in trade for other items] and I have one in each car. I run 195 thermostats and never go 15 degrees over. Very nice upgrade.

 I really miss that guy. Pretty sharp knife in the drawer...

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My explanation was hard to understand, I removed the bottom petcock untill coolant stopped, started car until last of coolant poured out then filled with fresh water while it was running until drainage was clear. Shut off engine, let drain. Capacity is about 2 gallons so after closing the petcock and poured the full strength gallon into the system then poured about 5 quarts clean water with heater on high and reserve bottle to cold. Down here for extra profits they sell half strength coolant fot the same price, to avoid having to use half of what you bought when you are just topping up. Theoretically it should cost half of the full strength stuff. Oh well when is two segments over 12 o clock and I start rollimg at constant speed (45-50)temp will drop to normal. Any suggestions on radiator flush?

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Looks like a previous owner dib not us antifreeze in Miami. Side flow radiator used plain water. The person I bought it from just drained the water and added enough to give the coolant to give it a green tint. New rad installed and removed side tank and it was half clogged with corrosion everything's good now. Thanks for everybodys help.

Richard

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Forgot to mention that down here my AC is on high 50 weeks a year. I am pretty sure that the radiator fans are on high when AC is on.

Edited by Richard D (see edit history)

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When the A/C is on..... both fans run, but only at 1/2 speed.......if the water temp goes to around 220 then they go to high

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During the trip/cruise to Silver Spring/Cedar key with the air on max, my 88 sat between 181 and 185 the whole time. I do have a 180 superstat and reprogrammed to bring the LO fan in at 181 and the HI at 185.

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Earlier this summer I replaced the Radiator on the Reatta I currently have. For years both of my 1990 Reattas, like many I have read about on this site, ran somewhat hot when driving round town ... it made me nervous. Neither car’s temperature went as far as the Red but did stay quite a bit to the right of 12:00 ... on the highway it was okay. This summer in Sarasota, Florida the temperature, humidity and dew point have all been extremely high so it has been like driving on the Sahara Desert yet the Reatta ran as cool as a cucumber; stayed at 12:00 except when in bumper to bumper traffic and even then only went one notch past. Honestly, since our cars are old and Radiators are inexpensive I recommend replacing the radiator as a maintenance or preventive measure ... I bet you would be pleasantly surprised at the difference it makes. John

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I had 2 radiators split this year. the 1990 Reatta and 1993 S-10 truck. 2 years ago my 1997 Saturn blew it's rad too. I think anything over 15 years is borrowed time on a plastic radiator.

All 3 were roughly $100 shipped for the rad itself on Amazon.

Edited by bhclark (see edit history)

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