I am a new owner of an 88 Samurai and new to fixing cars in general and I'm having an overheating issue and I'm hoping I could get a second opinion before I order the parts.

When I bought the car the temperature gauge wire was disconnected from the sensor and when I plugged it in I noticed the temperature would rise to max very quickly after starting the car. I tried removing the radiator cap then running the engine to see if coolant was flowing and I could see no change. How long should it take before the coolant starts flowing?

I replaced the thermostat and the coolant still isn't moving so at this point I think it is either the water pump or the radiator. Is there any way to narrow down what the problem is without taking the water pump off? Is there anything else that could cause the problem I haven't thought of?

I've never really worked on cars before so I'm a little leary of pulling the timing belt off and there may be something simple I am overlooking. Thanks for your help.

I want to suggest you get help rather than ask questions on a forum - with limited experience you're going to be chasing your tail on this.

How quickly does the temperature rise?  With a cooling system in good working condition, there is no coolant flow until the thermostat opens, and the thermostat doesn't open until the engine is almost at operating temperature, which could take anywhere from 5~15 mins or more from a cold start - the time frame will vary depending on how cold it is where you are.  The way you say it rises quickly to the max makes me wonder if there is an actual overheat issue.

Get an IR thermometer and get numbers - how hot is the engine actually getting?  Is it really overheating, or is the gauge misleading you?  You can test the thermostat by suspending it in a pan of water and bringing it to the boil.

You can also remove the thermostat, reassemble the cooling system without it, and start the engine to check for a circulation issue - the thermostat is literally the only thing that should prevent circulation, so once it's out you should have flow, if not, check the radiator next, water pumps have been known to fail, but a failure to pump is not that common, in most cases, they are replaced because of a worn bearing or leaking seal.

Do not operate the engine without the thermostat on a long term basis, this should only be done for test purposes - if you're going to do it as a "get you home" measure, remove the center of the thermostat and replace the outer body.

I just went through this problem. After chasing my tail for several days, a fellow Zuk owner said to replace the radiator. He is a mechanic and builds rock crawlers professionally. Several people on Suzuki forums said the same thing. I was leery, but I ordered a new radiator from Autozone. They were running a promotion with $20 off and free shipping. I got it for less than $90 to my door.

I installed the radiator and a new t-stat. Problem solved!! It now runs at the 1/3rd point on the gauge.

I wouldn't worry about the temp gauge, my buddies 87 did that and it turned out it wasn't running hot at all. the Gauge was just bad. even after replacing the wiring and sensor it was still bad. I would go with a radiator.

I wouldn't worry about the temp gauge, my buddies 87 did that and it turned out it wasn't running hot at all. the Gauge was just bad. even after replacing the wiring and sensor it was still bad. I would go with a radiator.

If you think he has a gauge problem, why would you suggest he change the radiator?

Follow fordem's suggestions, they actually make sense.

Quote from: TheLastSamurai on August 26, 2015, 02:02:15 PM

I wouldn't worry about the temp gauge, my buddies 87 did that and it turned out it wasn't running hot at all. the Gauge was just bad. even after replacing the wiring and sensor it was still bad. I would go with a radiator.

If you think he has a gauge problem, why would you suggest he change the radiator?

Follow fordem's suggestions, they actually make sense.

I was more or less weighing in on others advice. Now that I read it as an individual piece of advice I see how it doesn't make any sense.

 First of all the Samurai gauges are of poor quality at best.
I always recommend adding mechanical gauges.
Second, a thermostat more than likely would have solved your issue.
 No flow with a high reading ( even on a poorly functioning gauge ) is an indicator of a bad thermostat.
Unless your radiator is leaking or clogged from running sediment laden coolant,  you original radiator was probably fine .
And I might add , is generally a better unit ( Brass ) than nearly all replacements.  Especially aluminum...........

 I know that this doesn't help the PO at this point as he has already replaced the majority of his cooling system at this time and seems to have solved his problem.

 I have been out of this loop for some time and am just getting back to this board as we speak. Sorry.