Hi, I noticed my ratiator was leaking the other day. I'm going to have it replaced but wondered why it would start leaking?

My machanic thought the thermastat might have went out, he didn't check out the water pump but I was thinking that might possibly be bad too?

 

The leaking could be coming from a number of different areas. Check your hoses, clamps, radiator, thermostat housing and water pump. Just do a compression check on the coolant sytem. It will tell you if the water pump is up to spec. I'm not sure what the factory compression is supposed to be. I'd get a 2nd opinion before I'd let someone start pulling my coolant system apart. Could be as simple as a bad hose. Never know till you get under there and check.

 

also are you sure that it is not your coolant reservoir....that is leaking...sometimes it drips on the radiator...and mine needed to be replaced..

CEO

 

Its the radiator itself. We were reving the engine and it would almost spray it out, its cracked in a few places. Not sure how it happened, but i'm guessing it just happened from age

Anyway, I just wanted to know if it was common for the water pump to go out? Or is it common that it goes out when the radiotor leaks? I was making a pretty loud noise, but one we filled the system with water again it stopped.

 

It would be pretty hard to do a compression check on the system with a leak. What year and how many miles on your SC? My WP went out at 100k.

 

92 sc400, 107,000 miles

If the water pump went out it could cause the radiator to spring a leak couldn't it? I noticed it was plastic, maybe it melted?

 

That noise was your water pump working. I don't really see how a bad water pump could make your radiator spring a leak. Best thing to do is replace the radiator. Maybe even get a shiny new aluminum one from Fluidyne or another aftermaket company. Probably cost about the same as a new Lexus radiator. Then do the compression test on the coolant system. You don't need the radiator out to replace the WP anyway. The WP might have a plastic housing but the WP itself is metal.

One thing to remember is when you replace the water pump there is alot of other things that should be done. New timing belt. Cam covers. Tensioners. If it doesn't need to be done then don't worry about it.

 

Thanks for the info vegas, I'll just replace the radiator and hope everything works.

I found this one, its under $200. Has anyone used these guys before?

http://overnightradiator.com/lexus-sc400-radiator.html

 

Last year, this year or next year most early 1992 SC's will have a plastic top tank failure. New top tank is available from Lexus - they will have part in stock. Common failure. Rest of radiator will be ok.
Get new top tank and maybe the seal too and radiator guy can fit it.
Mine went last week.
So many of my mates have had theirs go as well. One even lost the motor! So check the top tank - cheaper than the whole radiator.

 

The top tank in mine went a couple of months ago, and as UZZ32 said it was only the top tank that needed a fix, everything else was fine. For about AUD$300 it's a pretty cheap safeguard against stuffing something else up like a blown head gasket. I didn't want to risk it so I replaced it ASAP and all is well, no leaks at all.