Geo Prizm

So larger the Bulb so biger the movement of the indicator colum at changes of temperature.

Hope it helps
Fritz

All bulb thermometers use a fairly large bulb and a narrow tube to accentuate the change in volume.

Two things could cause the tire to make a noise sounding like a flat tire even though the tire is fully inflated. First, if the tire has a big enough flat spot on the tread surface and second if the radial plies in the tire have separated letting air between the belts causing patches of the tread surface to bulge.

I've been working on this for a 1993 Geo Prizm 1.6L engine. So far it's a phenominally complex and involved process that I wish i had paid someone to do.

Here is an overview. (based on my memory) it might get you pointed in the right direction.

Drain Coolant.

The following items will need to be removed/Disconnected in the following generalized order.

Battery Cable, Passenger side front tire, splash guard over the engine (behind the removed tire, all three belts, Alternator, Air compressor, Alternator and Air compressor Mounting Brackets (attached to tensioner pully), Spark Plugs, Valve cover, WindShield Wiper Fluid Resivoir, Top two timing Belt covers, The Belt wheel on the Water pump, the oil dip stick.

Replace Water pump and gaskets (and whatever other parts you can because you don't want to do this again)

Flush coolant system with water hose.

Put everything back together in reverse order.

Answer

I replaced the water pump on a 1994 Geo Prizm (1.6L) about 4 months ago. Keep in mind instructions for the Geo Prizm and Toyota Corolla are generally the same since they are derived from the same platform. The mainstream engine for both vehicles is the 4AFE for the 1.6L and 7AFE for the 1.8L Since I did this a few months ago I won't be able to list all of the steps in detail bu I will list the general steps I followed.

1. This job took me about 5 hours.

2. Both Geo and Toyota service manuals (and instructions on Autozone, etc.) state you must remove various engine mounts in order to lift the engine. This would make the job easier but it not required. The only reason I can see to lift the engine is to remove the water pump pulley. I also did not remove the wheel. More on that below.

3. I would recommend you have ratcheting box wrenches (10mm, 12mm) and a set of offset box wrenches.

4. Disconnect the battery cable.

5. Drain the coolant by opening the drain cock on the bottom of the radiator.

6. Loosen the retaining bolts on the power steering pump, alternator and A/C compressor.

7. Loosen the locking bolts (probably 10mm) on each tensioner and then turn the tensioner bolts counter clockwise (I think!) to loosen the fan belts. Remove the fan belts.

8. Remove the power steering pump bracket (mine looks brass/gold color) to allow easier access to other components.

You may not have to do the following (steps 9 through 12) if you are not replacing the water inlet hose which connects to the back of the water pump but mine burst and I had to replace it. Go to Toyota or Chevrolet for the replacement. It costs about $10 for a 3" piece of hose but it fits perfectly. I would not waste my time trying to get a longer piece and cutting it myself.

If you do replace this I recommend new clamps (the type that you can tighten with a screwdriver or wrench) instead of the original "spring" clamps. The spring clamps are difficult to get on (no pliers in this tight area) and you can get a ratchet with exception in there very easily.

9. Remove the electrical connector (fan thermostat switch) on the pipe connected to the water inlet pipe.

10. Remove the wiring harness retainer bolt. This is on the side of the engine near the center. In order to remove the inlet pipe you need to remove the plastic portion of the harness holder which overlays the inlet pipe stud.

11. Remove the water inlet pipe and hose and oil dipstick.

Here is the tough part.

12. Use an offset box wrench to remove the 4 water pump pulley bolts. There is very little working space between the pulley and the engine compartment. Once you get these 4 bots off my recollection is you cannot remove the pulley itself. This is why you need to lift the engine. But removing the pulley is not necessary. With the pulley loose you have enough room to remove the timing cover bolts.

13. Make sure you remove the A/C compressor and bolts holding the compressor mounting bracket. You can suspend the compressor by thick wire. If you do not remove the compressor mounting bracket it is nearly impossible to get to the 2nd/middle timing cover mounting bolts on the right hand side. I did not perform this step and wasted about 2 hours removing and replacing a single bolt.

Back to easier stuff.

14. Remove the engine wiring harness retainer on the valve cover. You need to do this to remove the valve cove. My valve cover was frozen so I used a rubber mallet to free it. You should also replace this gasket (but I did not and most shops probably don't either).

16. Remove all bolts on the top and middle timing belt covers. You do not need to remove the bottom cover. The bolt on the lower left behind the water pump pulley is also a killer. I used ratcheting (10mm?) box wrench.

I recommend stuffing rags down into the bottom cover. You don't want to drop a bolt down there or get residual coolant on the timing belt when you remove the water pump. I also purchased a telescopic part grabber with magnetic tip ($2 at Kragen) to pick up dropped bolts just in case.

17. The water pump retaining bolts should now be exposed. If you are removing the entire water pump (with housing - basically the part on back which connects to the water inlet hose) then you need to only remove 3 bolts. It only costs about $10-15 more with the housing so that's what I used. By the way it's much cheaper to get these on the Internet (I got an OEM Aisin if I recall). Same one used by Toyota but about $50 instead of $100.

18. Once the water pump is removed you should probably replace the O-ring which creates a seal between the pump and engine block. You will need to carefully pry it out (I used a utility knife to catch an edge, then pull it out don't try to scape it out). You should be able to get this at your local parts store but they did not have it so I went to Toyota (about $8 yikes) but I had no choice at the time. I also had problems with this seal staying in place when I seated the water pump so I just put enough gasket sealer in the groove to hold in place.

19. Remount the water pump.

If I recall correctly you need to put the pulley on the pump. Do not bolt it since it will not fit between the engine and the engine compartment. It must remain loose but this is the time you need to put it on. I also recall you will need to do some maneuvering here to get the pump/pulley back in place. Don't give up it cal be done.

20. Remove the rags and remount everything.

** The most difficult part is getting the water pump pulley holes aligned since there is very little working room (just like when it was taken off). It took me about 10 minutes of trial and error to get a bolt into the pulley.

The lower left timing belt cover was also difficult.

You may also have trouble getting the inlet hose back on. I just put some water/antifreeze on it and then it slipped on pretty easily.

21. Refill your radiator, connect the battery cable and you are all done.

Comments:

This is not an easy job by any means but with the exception of the water pump pulley and timing cover bolts it is straight forward. I figure I could have made this a 4 hour job instead of 6 if I would have remove the A/C compressor and mounting bracket.

Make sure you have the tools to complete this job. You should see if you can get a wrench on the pulley bolts. If not then you need a different wrench. You should identify where the timing cover bolts are and think about how you will remove them and if your tools can do the job. It was worth it for me. Now I am debating if I should change the timing belt myself. Everything seems straightforward except removing the crankshaft pulley bolt and pulley. I will post if I do it.

Hope this helps.