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thermostat

26K views 24 replies 7 participants last post by  bcarter5 
#1 ·
which thermostat for 1988 samurai is the 195 degree too hot? seem to be having running hot problems since i installed it
 
#2 ·
thermostat...

Did you install it upside down?

The spring side of the thermostat should be down so that the temperature-sensitive spring metal is in contact with the the hot engine coolant so it can open the valve plate.

I hope that this helps!
 
#4 ·
The only other suggestions are:

New thermostat

Check the radiator fan to see if the fan clutch is working. The fan should turn by hand - but only after applying some pressure. If it turns freely, the fan assembly needs to be replaced.

New water pump. If this is the case, DO NOT attempt to remove the timing belt cover by loosening the big 17mm bolt in the center of the crankshaft! There are 4 smaller bolts that hold the accessory pulley to the crankshaft via the crankshaft timing pulley. Remove those 4 bolts in order to remove the accessory pulley! Refer to the Samurai Factory Service Manual - a downloadable pdf file at Ack's FAQ (see signature below for the link) - for detailed information. Do a search for fsm and select the '88 Samurai FSM link.

I hope that this helps!
 
#7 ·
No, a 165 degree thermostat will not work properly. The engine will run best at the right operating temperature, which is determined by a 195 degree thermostat.

The cheap solution (165 degree thermostat) will only be a band-aid solution.

You really need to check the fan clutch, belt tightness and look for problems with the water pump.

Try running the engine from cold with the radiator cap removed. If the water pump is working there should be circulaton seen when looking into the top of the radiator core. If not, remove the thermostat then look again. If there is still no circulation then you probably have a water pump problem. Remove the belt and hand-turn the pump. If it is hard to turn it's replacment time.

Also, check the water pump drive belt to see if it is tight. If it is loose, you might have belt squealing and charging problems.

I hope that this helps!
 
#8 ·
changed the waterpump today.the mech ordered a 160 degree t/stat.dont know why he did.i am going to put a new 180 or 195 which ever i can find today. he left the stat out does not run hot anymore but the heat wont work either. thanks for your help
 
#10 ·
Remember, the thermostat doesn't really control if it cools or not, it just controls at what temp the engine runs at. Your cooling system cools.
If you are overheating or running hot, make sure you ARE running hot. Is the temp gauge right? If so, as someone else said, check your flow (water pump). How old is the radiator? Is it clogged? Fan shroud on? How are the fins? I do my mix stronger than 50/50.
I've got a friend that can't understand why his rig runs hot... he has so much crap in front of his rat it is amazing. Bumper, air horns with compressor, this, that... gee, it runs hot, wonder why...
All that said, years ago I used to run a cooler thermostat and hotter plugs in the summer, then change back in the winter. Once a year I did a total flush. That was back when I had money. :)
I also have a electric fan in front for when I rock craw. Then again, I also have more than one heater core and fan. (got tired of the wife saying she was cold, now I can roast her)
 
#12 ·
The temperature gauge isn't a problem... it's an indicator of a problem. Find and fix the problem instead of hiding the indicator. drilling a hole is going to make your gauge tell you what you want it to say, but if there is a restriction in your core or the pump isn't moving the coolant bacause of a worn part or blockage, then you'll just be masking the problem for a catestrophic failure down the road. You may have a damaged EGR valve and your combustion chamber and exhaust are too hot. Circulating more coolant will keep the coolant temp down, but you won't be able to keep the manifold cool enough to prevent warping of the heads or valve seats.
 
#15 ·
Yes, The hole is just an air bleed so that air doesn't get traped below the stat and keep coolant from touching it. That would cause it to not open until it got very hot first. Usually it only occurs on a freash fill up from removal. Just my thoughts tho. I have been wrong before.
 
#16 ·
thanks for the info.i will look a little deeper.the 160 degree seemed to work fine but the heater was not warm enough.i disconnected the sensor below the gauge sensor and the gauge never moved past the normal position.not sure if i need the sensor or not.it goes to the computer i think
 
#17 ·
temp sender...

The Temperature Sender on a North American Samurai is connected directly to the dash temperature meter and nowhere else.

See this diagram:

Ack's FAQ: Your 4X4 Portal To All Things Suzuki/Geo

If you define "a lot hotter" as reading half way up the scale to the red on the temperature meter, that is a normal reading. Hot is in - or just before - the red.

You can find troubleshooting information on both the temperature sender and the temperature meter in the '88 Samurai Factory Service manual at Ack's FAQ. It is on page 21-11 which is located in part three of the FSM at the following URL:

http://www.acksfaq.com/pdfs/sam8817-7-end.pdf

The entire FSM in a downloadable PDF file form is at:

Ack's FAQ Samurai 1988 Factory Service Manual FSM

I sincerely hope that this helps!
 
#18 ·
from what I understand, the coolant bypass hole in the newer thermostats is to eleviate pressure build up on the engine side which causes the thermostat to be held closed. Almost all newer thermostats are built with this hole. It's not large enough to cool your engine down but it may help your thermostat open on time
 
#21 ·
thermal switch is for cutting the engine before you do serious damage from overheat.

The EGR valve is located just below the throttlebody on the intake manifold. It recirculates exhaust gas into the intake to cool down the combustion temperatures. The oxygen sensor is on the lower area of the exhaust manifold.
 
#23 ·
when the engine is cold, rev it a little while touching the diaphragm on your EGR valve, it should not move.

Let the Zook warm up and repeat the check. The diaphragm should now move when you rev it.

Checking the overheat switch... I dunno... send a voltage across your temp sensor that would indicate an overheat and see if it kills your engine. I don't know what the voltage range is on the temp sensor, and untill you know, don't go applying any votage to it or you'll end up frying your sensors and the limited ECU that the samurai has.

Unless you have a lambda sensor for the O2, there's no way of checking to see if it's accurate. You can see if its working with a volt meter. It puts out a low voltage signal when working properly .
 
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