Ok so I have a 87 samurai stock I've changed the water pump and thermostat and it is still over heating bad any advise u can give would be great thanks

Was it over heating before you changed your thermostat?  If it wasn't, I'd check the new thermostat. New ones are sometimes bad.

Is your coolant circulating properly in your radiator?

I developed an overheating problem on my '91 Sidekick 20 years ago.  I changed the water pump.  Still overheated.  Had the radiator flushed.  Still over heated.  Finally, I started it and let it warm up to normal operating temp then raised the RPMs from the engine compartment.  I watched the radiator hoses as I accelerated the engine.  I immediately noticed the added suction from increased RPMs on the water pump was collapsing my upper radiator hose because of a lack of flow through my radiator.  It was sucking a vacuum into the hose.  You couldn't see this happen while sitting in the truck.  I bought a new radiator.  Problem solved.  The shop had flushed the old radiator, it didn't leak, but it also wasn't allowing the full flow of coolant through it at operating RPMs.

This may not be your problem, but it demonstrates the cause can be from several sources, some unexpected.  If you have an original radiator, it may be the problem or part of the problem.

First - what do you define as overheating - temperature gauge in the red?  boiling over?

Second - under what circumstances does it overheat?  All the time?  In heavy traffic only?  On the highway?  In low 4 uphill?

Not all overheat symptoms are actually overheating.

It seems as we are both having the same problem. I'm not trying to hijack your thread. My Zuk started to over heat this morning.

Decided to head up to Silver City, ID this morning with my father in law. Loaded up the 10/22's and headed to Murphy to have breakfast at the Murphy General Store and Café. Left Murphy for Silver City, about 7 miles up the Silver City Road, Goldilocks starts over heating like a big dog!!!!! Its 72 degrees outside, two days ago it was 99 degrees and no problems when driving into Boise.

I pull over to see what the problem is. When I open the hood the radiator is boiling water out into the catch bottle and the bottle is leaking. I figure that this has been going on for a while and the radiator is low because it could not suck back coolant when it started to cool because the overflow bottle is leaking. No big deal. There is a creek right next to us in the canyon with plenty of water. We empty out the ammo can and fill it with fresh water and wait for the engine to cool down. After an hour I have the FIL start the motor and I slowly pour in the creek water. Everything looks good to go. We take off up the mountain and in five minutes its over heating again. We decide to turn around and head back home. The temp is running high. but is not in the red. All the way home the gauge is running about 7/8 of way up the gauge. It has never done this before.

The day before I had replaced the distributor O-rings. I thought maybe the timing was too far advanced and causing the motor to run hot. Nope, that wasn't it, timing was dead-on at 10 degrees and idle at 800 RPM. I went to Auto Zone and picked up a new 180 t-stat, gasket and 13lb rad cap. Installed those, topped off the coolant and headed back to Silver City. Before we drove 7 miles it was over heating again, only now just below the lower red line on the gauge.

I have no idea what is going on. The Zuk is running really good except for the overheating part. It has never done this since I have owned it, almost 2 years now.  As we were starting out this morning I was commenting to my FIL about how good the Zuk was running and that I finally cured the steering shake at 40 MPH.(replaced the draglink, tie rod assembly, drivers side tie rod and set the toe in.) Taking care of one problem at a time and now this overheating gremlin rears its ugly head!

Any help would be appreciated.

What's the elevation around Silver City?  5500-5700 feet above sea level?  How much antifreeze mix do you have in your Sammy's radiator now that you added all the fresh stream water?

Water boils at 212 degrees at sea level and then for every added 500 feet of elevation,, it's boiling point drops by one degree.  So... IF your elevation was around 5500-5700 feet the water in your radiator would start boiling when it reached around 200 degrees.  Antifreeze also raises the boiling point of water (besides reducing its freezing point).

So maybe your Sammy's cooling system is degraded from age and build up inside the radiator, it doesn't cool as well as it did, and the added pure water just lowered the boiling point of the liquid in your radiator to the point where the two couldn't keep the liquid below 200 degrees?

My next guess is your radiator needs flushed or replaced and then the next would be a water pump problem.

But I think your main problem is the lack of coolant mix in your cooling system.

melbakid - I want to take you back to the first question I asked earlier - what do you define as overheating?

In the first instance, you had a "boil over", which you're attributing to a lack of coolant, in the second & third instances, you're talking about the temperature gauge reading, with no mention of boil over, so is it overheating or simply running hotter than normal?

You seem to be heading up a mountain road, presumably, the engine is working harder than normal, and therefore generating more heat than normal.

In addition to nprecon's comments on a degraded cooling system, another possibility is a defective fan clutch, especially if your progress up the mountain is slow, so in addition to the extra heat, there's reduced air flow.

I'm not certain what effect elevation would/should have on the cooling system operation, yes, elevation does have an impact on boiling point because of reduced atmospheric pressure, but the cooling system is not, or should not be at atmospheric pressure (reduced or not), it's a pressurized system, and the pressure at which the radiator cap is going to lift off of it's seat is determined by a spring, which is not taking atmospheric pressure into consideration.

What's the elevation around Silver City?  5500-5700 feet above sea level?  How much antifreeze mix do you have in your Sammy's radiator now that you added all the fresh stream water?

Water boils at 212 degrees at sea level and then for every added 500 feet of elevation,, it's boiling point drops by one degree.  So... IF your elevation was around 5500-5700 feet the water in your radiator would start boiling when it reached around 200 degrees.  Antifreeze also raises the boiling point of water (besides reducing its freezing point).

So maybe your Sammy's cooling system is degraded from age and build up inside the radiator, it doesn't cool as well as it did, and the added pure water just lowered the boiling point of the liquid in your radiator to the point where the two couldn't keep the liquid below 200 degrees?

My next guess is your radiator needs flushed or replaced and then the next would be a water pump problem.

But I think your main problem is the lack of coolant mix in your cooling system.

The elevation is at 5000'+, although we never got that high up the mountain.

I run a 50/50 mix in the radiator.

After I we got home, I replaced the t-stat and rad cap. Redid the coolant mix to 50/50. Let it idle in the drive way to heat up and check for leaks. Everything was ok. Took it for a test drive and drove seven miles. At the end of seven miles the gauge was just at the bottom of the red zone,(running higher then when we were in the mountains) a hair from touching the red line. I did not want to go any further and risk warping the head. Outside temp was in the low 80's through out the day.

The radiator looked nice looking through the fill hole. When I replaced the t-stat it looked clean in the housing. I have had aluminum engines before,(1963 Alpha Romeo Spyder Veloce) so I am aware of corrosion with aluminum engines due to dissimilar metals.

melbakid - I want to take you back to the first question I asked earlier - what do you define as overheating?

In the first instance, you had a "boil over", which you're attributing to a lack of coolant, in the second & third instances, you're talking about the temperature gauge reading, with no mention of boil over, so is it overheating or simply running hotter than normal?

The first instance was a boil over, which I thought might be from lack of coolant due to a leaky coolant recovery bottle. The second instance it was running hotter then normal. Normally the gauge is sitting at the half way mark, in this case it was at the top of the mark of the yellow area. I did not want to take a chance of it going into the red zone, so I shut it off let it cool down and then drove it home with the gauge climbing back up to the top mark of the yellow zone.

After replacing the t-stat, rad cap, and coolant mix, I took it for a seven mile test drive and the temp climbed back up to the bottom mark of the red zone.

You seem to be heading up a mountain road, presumably, the engine is working harder than normal, and therefore generating more heat than normal.

In addition to nprecon's comments on a degraded cooling system, another possibility is a defective fan clutch, especially if your progress up the mountain is slow, so in addition to the extra heat, there's reduced air flow.

I did check the fan and it was functioning every time we stopped to check on the engine.

I'm not certain what effect elevation would/should have on the cooling system operation, yes, elevation does have an impact on boiling point because of reduced atmospheric pressure, but the cooling system is not, or should not be at atmospheric pressure (reduced or not), it's a pressurized system, and the pressure at which the radiator cap is going to lift off of it's seat is determined by a spring, which is not taking atmospheric pressure into consideration.

i understand you have replaced the cap, thermostat, checked the timing, and it's not running lean.

make sure the heater is getting filled.

pressure test the system.

the overflow tank will save you coolant and keep it topped off every cycle, and you'll want it after you get this figured out.

good luck

If it will idle for extended periods without overheating that eliminates the clutch fan as a possible cause, however a 7 minute drive is nothing of any significance, so unless there is something you forgot to mention, I don't see it as being an excessive heat generation issue, so that leaves insufficient heat dissipation - either insufficient circulation or a partially blocked radiator (either inside or outside), and looking through the fill hole is a very restricted view.

Not familiar with the '63 Alfa, but what dissimilar metals do we have here?  These are all aluminum engines, did the alfa have a cast iron block & alloy head?  That was a common configuration back then.

I agree.  Looking through the fill hole doesn't prove your radiator is sufficiently circulating or cooling the coolant.  I had the radiator in my '91 Sidekick flushed when I was chasing an over heating problem on it.  It was clean and looked great... but it was still clogged and wouldn't allow the coolant to circulate and cool properly. 

I opened the hood and ran the throttle up and I discovered every time I accelerated the upper hose would collapse from the suction.  I had already changed the hoses, so I figured I had a restricted flow issue.  Installed a new radiator and the over heating stopped as well as the hose collapsing.

I would like to thank everyone for their input.
Next step will be to order a new radiator. I think it would be better to replace it, rather than have it cleaned out. It's a plastic and aluminum model. Every plastic and aluminum radiator I have ever had has had problems.
Doe anyone make an all metal radiator for the Sammy?

There are probably others out there, but here's one offered from Low Range Off Road.  I paid right at $200 for my last aftermarket radiator (plastic and aluminum) a couple years ago, so this metal one appears to be a decent price point.

http://www.lowrangeoffroad.com/suzuki-samurai-economy-full-aluminum-radiator.html

Ok so I have a 87 samurai stock I've changed the water pump and thermostat and it is still over heating bad any advise u can give would be great thanks

has this been of help?

Yes, this has been very helpful.
I seem to be having a problem with my computer. Every time I tried to post yesterday and last night, when I hit the enter key, the screen said this page could not be displayed. When I tried to refresh or go back it would wipe out every thing I posted and I would have to restart the post. After 7 times I got frustrated and just signed off.
Kind of how the last three days have gone. Everything has turned to shyte. Hopefully this post will get through.

I did contact Low Range, they sell the rad for $169. Except they are on back order with no ETA available. Trail Tough has them also, but for $229. Low Range told me they were the supplier for Trail Tough. Roadless gear has them for $200 and Petroworks has them for $165 and in stock according to their website.

I will try to call Petroworks and order from them.

Thanks to all for your help and replies.

Any of those vendors are top notch peeples.  You can't go wrong with any of them.  Appears Petroworks has an excellent price point on their radiators!