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View Full Version : Hello. Coolant/flush question.


gotpnoy?
06-26-2012, 04:22 AM
Hi. New guy here with a 1990 240sx 5spd fastback stock and question. (yes, i used the search button). ty

This is a long story. sorry.

So I went to Henry Coe State Park in Morgan Hill on a very hot day. Once I got to the top, my coolant reservoir was boiling/bubbling. Going up the hill, I didn't even notice my gauge go up. I look inside the reservoir and I see murky brown coolant. It didn't over heat though. I figured i'd flush it the next day.

...Long story short. I got the car (stock) from an old man 4 months ago and all i've done to it so far are oil changes. I figured they've flushed the radiator before I bought it.... I was wrong..

(1) First, I tried to flush it, correctly, but the drain plug on the block WOULD NOT come off (i used wd-40 and some other spray)! So I just drained the radiator, and ran water through the radiator while the engine was running (opened rad. cap and air plug) and made sure the water that came out was clear. During the 3x i was repeating this, the water would always be dirty brown.

(2) Next, closed the drain cock, fill radiator with water, and bled it. Start the car and let it warm up. Did this about 2 times. Then back to (1) again. I cleaned the radiator reservoir and replaced the radiator cap.

Finally, I drained the water with air relief plug open and filled radiator with 50/50 mix coolant to the neck. Then i bled it.

Also, the screw grooves that is on the intake/fan is gone, and the bolt that holds the fan has a stripped head. Now, i can't replace the thermostat. KA24E's thermostat is impossible to get to without taking the fan and the intake off.:mad:

Took the car for an hr ride to see if it would have any heating issues, but nothing, so its good. I came home, checked the reservoir tank and again, dirty brown liquid. I tried to open the radiator cap (i know that the engine was hot and it was a bad idea, but i wanted to see what would happen in the reservoir tank) and at about half a turn, a lot of dirty brown coolant would flow in the reservoir tank.

My only option in regards to the stuck drain plug on the block and the thermostat is to take to the shop. Flush in my area is $180 at a nissan dealership, and $170 at a shop and that is without replacing the thermostat. I've asked if they could take off the bolt and screws that are stripped for free, and they said it's $80 charge. LOL!

I am thinking that all this brown stuff and the time that it hasn't been flushed has rusted the radiator. I was thinking of getting a new radiator from courtesy but it's like $400, but i do not have that much.

RADIATOR ASSY - 240SX (S13) 1989-1990 SOHC M/T :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com (http://www.courtesyparts.com/21400-radiator-assy-240sx-s13-1989-1990-sohc-m/t-p-184472.html?cPath=1418_1419_1444_1448&)

How many times can i flush a radiator without damaging the engine/radiator/cooling system? Is it really important to take the drain plug off the block while you drain the coolant? What other methods should i do?

I am planning on swapping my KA24E with either s13 SR red top or an RB, when i get a job and some money saved up.

Promise Land
06-26-2012, 11:27 AM
Rather than going for an OEM radiator, I'd upgrade it for an Isis, Koyo, Mishimoto, etc. It would be cheaper ~$200 and give you better cooling potential.

I wouldn't think flushing the radiator would damage the system. Perhaps running a flush additive to clean out the gunk would help?

ka4life87
06-26-2012, 12:25 PM
Is it auto for 5 speed? If auto, trans cooler in radiator might be leaking and coolant is mixing with atf

AutechKouki
06-26-2012, 01:40 PM
A dealer will for sure not back flush your coolant. How do I know? I work at one. You'll get a drain and fill. That is all.

Your problem is the the iron block is corroded in the water passages. There's no easy way of getting rid of that corrosion, even if the block was bare.

And never ask any shop to perform work for free, just like you they have to make a living.

For your stripped bolts get a vise grip. Plus you really want a crappy oem radiator? Mishimoto has dual row rads for KA with lifetime warranty for around $200, cooling is superior.

In my personal opinion other than a coolant issue it sounds like you have a cooling issue. Maybe your clutch fan is going out or I'd your car has a secondary electric fan it might not be coming on.