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Radiator flush

5K views 21 replies 5 participants last post by  robbpa 
#1 ·
Flushed out me radiator yesterday with the recommended amount of food grade citric acid and instructions found i the forum searches. My car was running a little hot and this seemed to work. I went in the house for a few minutes to let the car cool off a bit before draining, and when I went back out, the acid flush was draining on it's own. Seems it ate a hole in one of my tubes. This did not upset me since it was a 27 year old radiator so I ordered another radiator and thermostat. I have a question though, I've gone through the forum search and the cd and can't come up with a conclusion where the thermostat is. Is it on top or on the side of the water pump? I believe on my 87 420 sel it was on the side of the pump. Also, the thermostat I ordered was the alien looking thing with the 4 arms on top. I believe my 420 sel took something more normal looking.
 
#3 ·
Gen I cars the thermostat is on top of the water pump.
Gen II cars the thermostat is on the left side (facing the Water pump) of the water pump.

I had thought they all were on top, until I removed the top portion of my Gen II water pump and the thermostat was not there and the new one would not have fit. then I found the real Thermostat cover on the left side.
 
#6 ·
My car has the 3.8 V-8 so I'm sure what you say is the same for my car. I never had to change the thermostat on any of the other cars I owned except my 420 sel and that was on the side of the pump. But looking at the manual is deceiving because they don't clearly differentiate between Gen1 and Gen2 models, they kind of lump everything together. And since this is my first Gen1 car, I kind of get lost sometimes.
 
#8 ·
Ok, I started to rip this apart. 2 bolts came out nice and easy. 3rd bolt under the distributor was a little tougher. I sprayed some CRC 350 and was working it back and forth then SNAP! Now what? Should I get a new waterpump since the car has 185,000 miles on it? I'm going to try some easy-outs this weekend, but are there any other options?
 
#9 ·
I did a CA flush and it ate out my heater block plug. Lucky yours were external parts, easy to swap.
 
#11 ·
I don't know how lucky I am, my thermostat got stuck in the closed position so I still have some of the flush left in the block. Right now I'm worried about the heater core, freeze-out plugs, the head and intake gaskets. I'm going to get the thermostat housing off tonight and flush the whole system with water and do a lot of praying...
 
#10 ·
I broke a bolt off in my water pump and ended up just replacing the whole pump.
 
#14 ·
Ok, I bit the bullet and ordered a new water pump. It should be here at the end of the week along with the new radiator. Can someone tell me if the procedure is basically the same between Gen 1 and Gen 2 cars when replacing the water pumps? Or is there a thread in the forums that I missed? What should I watch out for? I downloaded Mclare's DIY thread since it's better than whats on the CD's. I just want to make sure I do this once and not "F" anything else up.
 
#15 ·
The biggest difference between the Gen I and Gen II water pump removal is on the Gen I the water pump has a removable casting on the left, (top and bottom hose connections). The gasket between this casting and the water pump has to be replaced, the Thermostat casting is on top and not on the side like Gen II's. Rest is pretty much self explanatory.
 
#17 ·
You can never tell with these units. At least Bosch is a fairly reputable brand. And, btw, I got my replacement bolt from NAPA. They have an assortment of high grade steel bolts with different threads and lengths from which to choose. I had to go to the counter for this as at my local NAPA the bolts are not accessible by customers.
 
#20 ·
Got the old water pump off this weekend and cleaned up the front of the motor. I brought all the bolts into work this morning to wire wheel them and get them cleaned up. Still waiting on the pump, should be here by Wednesday. I've been reading up on the water pump install and have mixed feelings about using any kind of sealant on the gasket. I bought water pump silicone, but I'm still on the fence about it. I definitely don't want to do this over again ... any suggestions?
 
#21 ·
I only used a small bead of sealant on the WP side of the gasket. None on the engine side. I did not want to have to deal with cleaning off the engine of sealant if my new WP failed for some reason. I honestly think you will be fine without it. Just torque the bolts appropriately. I decided to use it simply on the recommendation of a friend who was helping me. He did have more experience in these matters.
 
#22 ·
Ok, this wasn't as bad as I thought it would be. It went pretty smoothly and I modified some of the information from the DIY threads and searces I did. First, I only took the belts off the alt, ps pump and ac, I did not remove any of the accesories. Second, I pulled the distributor but did not put the motor on top dead center. Instead I took a picture of where the rotor was and marked it's position with a white paint pen on the outside of the housing. Third, I used the same paint pen and marked the pulley and harmonic balancer using the timing pointer on the water pump as a referance point. Problems I had... Harmonic balancer would not budge. I had to tap it with a hammer and use 2 prybars to walk it off. I used PB Blaster and steel wool on both the harmonic balancer and pulley to remove any rust on the inside lips and they slipped back on the crank with no problems when isntalled. Had both bolted on in less than 5 minutes. And the biggest PIA for me was the bolts on the viscus fan. I had the PS pump belts too tight and couldn't move the fan. My back is still sore from bending over and trying to get them to catch. I did this job in about 5 hours but I did it over the course of 2 weeks because I was waiting on parts. My advise to anyone attempting to replace their water pump is to make sure eveything is cleaned up while you are in there. Clean up your bolts and replace if they look "iffy" and use lots of penetrating oil and anti-seize compound on install.
 
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