COLD RADIATOR

[MICHAEL]

Hello, I have a 1997 Sidekick Sport 4 door manual tranny; it has the 2.3L motor swap -  bought 4 months ago.  As far as I know 1.8-2.3 are nearly the same?

I noticed that the radiator and lower rad hose are always cold.  The radiator and thermostat are new.  The water is hot on the water pump side, but cold on stat housing and below.  I am pretty sure all the air is out of the system.  I am only noticing this now, so may be normal this time of year?  It was quite hot out 4 months ago and I was crawling through the trails - never overheats or runs hot.  Needle is always in the middle of the gauge.  The hose coming out of the heater core is almost the same as going in.  I always hear water flowing in the heater core when upshifting (over 3000rpm or so).  I flushed/cleaned the heater core - no debris/water flow seemed good.
I just bought an IR gun today and measurements are as follows:

Cylinder head  -  160°F 
upper radiator hose  -  200°F 
lower radiator hose  - 110°F 
water pump   -  200°F 
upper heater hose   -  175°F 
lower heater hose. -  160°F 
lower rate radio lower heater hose pipe at water pump  - 200°F 

When I turn the engine off, there is a suction sort of sound in the upper radiator hose. What a pinch in the other three tiny water hoses see picture the suction immediately stops.


Any ideas?  

WELCOME ! Michael.
yes,  a 90deg F RAD drop  with that very good working radiator. (nice RAD and good rad fan too, parked)
this system also runs backwards, reverse fllow,   and other strange, ways too. let me explain them all. (try)
1: reverse flow. (as seen by the thermostat only)  such that pipe 22 is key to it working right.
2: even more odd the coolant (water) temp sensor is on the rear of the head not in the thermostat well, so the ETC sensor reads wrong all time time. (off set way higher) the ECU knows that and is happy there. ECT readings or IR GUN on rear, ECT metal housing will show way hotter than thermostat reading. (it run 180 so ECT might run 225?f) as head heats it up more.
the hottest water lands on heater core top hose and ECT both. and top rad hose

3: the cab heater must  flow water all the times (running sure) and its related bypass tubes, and if NOT the thermostat will fail open properly  or it will surge like mad.
it needs a custom 1.8L (up) thermostat for backwards flow systems  and has a rubber ring around there rim that must not be missing.
4; hose 22 and 19 must not be missing or blocked.

for there to be full  heater core drop  the blower must be on full and cold air is sucking into it, if not no drop happens or small 15f above is your drop


that suction sound to me is air is the system. not purged fully. getting it out can be hard in custom car like this. adding a purge port may be a cure.
looks to me all is ok but odd sounds.

nice car you built very nice and interesting too and thanks for sharing this, I love projects like this. lots of  fun this build, I am sure.

cheers and good luck , kick


THANKS FOR THE INFO.  2 QUESTIONS STILL:  IT'S A 180F STAT - WHY DOES IT NOT OPEN IF WATER BEHIND IS 200F?  ALSO, WHAT ARE THOSE TINY HOSES FOR?  LOOKS LIKE ONE GOES TO THE T.B. - CAN I RUN THE ENGINE WITH THE LONG ONE DISCONNECTED..FOR TESTING PURPOSES

SOUNDS LIKE I'D HAVE TO BE IN A DESERT BEFORE THAT STAT OPENS LOL. I HAVE A 4.5" LIFT;2" BODY LIFT; 33's; KRAWLER CASE; E-LOCKER