Suzuki Forums banner

Cooling System Confusion

3K views 17 replies 5 participants last post by  Porkins_eject 
#1 ·
Almost a week into owning my first Suzuki (1994 Sidekick, 2-dr, 1.6L 8V, 5-spd) of any kind and I'm stumped. Again. You guys have already helped me with a wiring gremlin and now the cooling system has me confused.

Temp gauge shows to be running right in the middle of its operating range when warmed up and is consistent. If I run the heater on high it's warm but not particularly hot. If you get it to temp (according to gauge) and touch the radiator tank it's barely warm. Upper rad hose feels warm but not hot like it should. Lower rad hose will barely be warm at all. Pop the rad cap and no pressure. Cap appears new and has shown no signs of leaking. Previous owner says the water pump had been changed recently and it appears as though that's true. It's much too clean and shiny to be very old. This evening I changed the thermostat and tested the old one in boiling water. It opened. I chased all the rad hoses and noticed they had some slight dips and humps that could be trapping air. I alleviated all of them. With a new thermostat in I ran it for an hr and never got it to burp. I got the same conditions as above. I fixed nothing apparently. My only places left to look (I think) are a new but bad pump or stopped up radiator/heater core. It seems to only be circulating a minimal amt of water and has shown no signs or symptoms of overheating. Are there multiple P/N's for the pump? Could it be some sort of wrong rotation situation? I've got the rad full of flush and plan to leave it for a day. See if it helps any. Otherwise I'm lost. Please help.
 
See less See more
#3 · (Edited)
I thought about an IR but the temps are so low at the rad and both hoses that I can leave my hands on them immediately after driving for extended periods. They're just way too cool for everything to be in working order. Oh and I don't have ready access to an IR on top of the fact the Mrs is running hot at how much $ I've already spent on it in less than a week. I really don't want to have to start sleeping in my lil Kick.
 
#5 ·
Aqua, I need a little guidance there. I'm not aware of the difference so what should I be looking for? However I should point out that after driving the thermostat housing is too hot to leave my hand on but the upper (and lower) hose will still be cool. Just like if the thermostat isn't opening but I installed a new and tested the old one. Doesn't seem to be circulating. I'm thinking about removing the thermostat completely and test driving to see if anything changes.
 
#6 ·
There are two types of thermostat housing for these cars, and yours, if original, will be the deep well housing, where there is a 4mm lip on the housing - you will need a 5mm o-ring around the thermostat, which often doesn't come with the thermostat but you must buy it separately. The thermostat must be snug in that housing, and the bleed hole in the thermostat facing the radiator. Your radiator cap must be 13psi (0.9 bar). I would probably flush the cooling system, but fresh coolant in it, check the thermostat (which should either be 180 to 195F), and buy an IR gun so that you can actually tell what the temps are. $10 at Harbot Freight.
By the way, the needle on the temp gauge is pretty meaningless - unless it is suddenly sitting in a place where it wasn't before. Mine has sat at 1/4 for 18 years.....
 
#7 ·
Bex, you and Aqua may be onto something. The o-ring may be my clue. I'll have to pull the thermostat housing again (which I will do shortly) but when I bought the new thermostat I was given a standard type gasket, not o-ring. When I removed the old stat it had the same paper gasket as I was given. Again, no o-ring. I just drained the rad after leaving flush in it overnight and nothing came out that looked of much concern. Also I put air pressure in the rad at the filler neck and air seemed to be blowing through the rad. Granted that's not the best test but I'm trying to make do.

To make sure I understand does the o-ring fit into the housing separately from the stat or is it wrapped around the edge of the stat itself? Oh and FYI both the old and new stats are 180's with bleed holes. I'm thinking the IR may have to happen too.
 
#8 ·
If you open up your thermostat housing, you should see that there is a bit of a 'well' about 4mm deep. If you look at the thermostats on this page:
1994 SUZUKI SIDEKICK Thermostat

you'll see that the photos in the top just show the thermostat, and the photos in the bottom show the o-ring in place around the perimeter of the thermostat. That's what you need. Paper gaskets not used after 1990/91.

Stant is considered a good quality replacement.
 
#9 ·
Just opened the stat housing up again and there appears to be a slight recess where the stat sits in the manifold, but not one in the neck. I'd post a pic but I'm not having much luck. Regardless, the non o-ring stat I have fits very snugly into that recess but it's possible that's a fluke. I measured the recess and it's only 1mm deep and roughly 2mm wide at the lip. I think I'm going to flush through again and then take the Stant P/N from your link, Bex, and get an o-ring version and see if it fits at all. I should point out that I've seen pics showing 2 different arrangements in how the stat may be oriented. One vertical and one horizontal. Mine sits in a horizontal fashion so it just drops into the manifold. Just passing that along if it helps any.
 
#11 ·
UPDATE: I took the stat I had out and flushed through both the engine and rad. Water passed through both easily with little trash. I then filled the cooling system up at the stat housing and got water to come up in the rad. I put the stat housing on, minus the thermostat itself, topped the system off with water and let it run. I could, for the first time, clearly see water circulating in the tank. I blocked off the rad with cardboard, put a thermometer into the filler neck at let it idle. It warmed to 155F and stayed there after extended idling. All the while water was circulating which it wasn't doing when I first noticed the prob. Just to double check myself I took the top hose off at the rad and started it. It quickly pumped all the water out. So it seems I've narrowed this down by eliminating possible pump failure or clogged rad. That seems to only leave the stat. But with that said I'm still very open to suggestions.
 
#12 ·
I believe the engine will not warm up properly without the thermostat in place. You need to install the thermostat, make sure it's properly seated. The thermostat must fit snugly to the top of the housing. As they stopped making the housing for the paper gasket in 1990/1, it is assumed that the thermostat housing for your car needs the o-ring. And as Aqua says, you need to make sure that the bleed hole is pointed to the radiator.
Look at the photos in post #8 here
http://www.suzuki-forums.com/suzuki...geo-tracker/48444-thermostat-replacement.html
 
#13 ·
I ran it w/o the stat to see if any water was visibly circulating. In doing so it was the first time I had clearly seen it. My fear was clogged rad/faulty water pump despite it (pump) being supposedly new. I have put it all back together now. The o-ring stat does not fit my engine. While there is a slight (1mm) recess in the intake it's not nearly large enough for the o-ring and the neck will not seat even remotely. So I went back with the gasket style but upon close inspection it's the only thing that would fit and seat properly. With it reassembled I drove it hard for several miles then checked the temp in the tank with an thermometer. 168F after hard driving on a 55F day. I don't know where to go from here. Nowhere I suppose. After having tinkered with my Kick for a few days I've found a lot of shoddy work. I guess I'm being over protective of my Wee Beastie. I did orient the stat as you guys said and it burped ever so slightly. I'll resume driving and follow up on this when Spring arrives. Thanks, thanks, thanks for your help.
 
#14 ·
What are the outside air temperatures where you are testing your cooling system?

All OEM cooling systems are designed to keep the engine cool even in the desert during the summer... pulling long grades... they MUST have more cooling capacity than you need most of the time. In colder (and normal) temperatures, The t-stat will be opening and closing as needed to keep the ENGINE at the correct temperature. This "riding the thermostat" is normal. When it is very cold, there will be a lot less flow through the radiator as the "waste" heat is being used to heat the cabin and other parts on the motor. (You see all the little water hoses running around the intake?)

Bottom line: The temperature of the radiator is not important as long as the motor is at the correct operating temperature.

To anyone who is worried about the heater hoses are different temperatures should realise the heater core IS a small radiator. (aka: heat exchanger) So one would expect the output to be lower temperature than the input.
 
#15 ·
It was mid 50's when I was testing. What scared me is it seemed like it had stopped circulating water when warmed up. Also, I understand the heater core is just a mini rad but it's worth mentioning as not everyone does. What started all of this was the temp differential between the intake and the rad hoses. I've never had a vehicle with such cold feeling hoses. My prior experience has been early GM iron, street rods, and a few Jeeps. I'm thinking my 1st Zuk carries a steep learning curve. That plus it has 300K worth of miles and neglect to sort out.
 
#17 ·
... What started all of this was the temp differential between the intake and the rad hoses. I've never had a vehicle with such cold feeling hoses. My prior experience has been early GM iron, street rods, and a few Jeeps. I'm thinking my 1st Zuk carries a steep learning curve. That plus it has 300K worth of miles and neglect to sort out.
The guy I sold my first Sidekick to was so worried about that he changed the water pump at the first visit stop (Salem Oregon) on his trip home to Wisconsin. If he had asked, I would have told him it was normal.... not sure he would have believed me.
 
#16 ·
1mm deep thermostat recess in the intake manifold means paper gasket. 4mm deep recess means thermostat with rubber surround. That's that. In a perfect world a 94 would have the 4mm recess but after 300k you never know what may have been swapped in there.

I had a thermostat that was sticking every now and then even though a stovetop test showed good, so I replaced it. Didn't wanna blow a head gasket over a $5 thermostat. Maybe your new one is bad? If thermostat housing is hot and hose is cool, that means the thermostat is not opening. It should get hot almost immediately after the thermostat opens. Another reason the top hose isn't getting hot is it may be full of air.

How is your overflow reservoir doing in all of this? If you've had anything more than the reservoir or radiator cap open (which you have), there is still some air that needs to come out, and if working properly it will push the air into the reservoir, and suck some coolant from the reservoir. It does both functions through the radiator cap, so make sure that the spring works, and that the little center vacuum valve works and the air passages in the cap are clean. Then check out the reservoir and its cap and hoses. Are they clean and free flowing? Is there sludge or even dead bugs in the reservoir that plug the hoses and radiator cap when the coolant tries to draw back? Mine at times was collapsing the radiator hoses after I shut it off. Some of the things I dealt with on mine but it's all good now.
 
#18 ·
Lol I wish someone had told me. Luckily my water pump had just been changed or I'd be elbow deep in that. I was getting ready to buy a new rad and who knows what else. I don't want to turn into a part swapper but it had me buffaloed. Much ado about nothing is better than a big prob I suppose. Now I'm off to figure where (or even if) I can find door seals. Read some good threads on here about door adjustments but my seals look ratty and leak bad.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top