Overheating!!!

[mattrose87]

So here's what I got

1987 samurai
85ish 1.6 td
Fresh rebuild
Everything top to bottom injection pump injectors new rad. Water pump EVERYTHING

Head and block both in great shape from machine shop

Also added intercooler and air oil cooler I tossed the water oil cooler.

Ok so got it back in the Sam and let it warm up and it got to 200 at idle took it maybe a 1/2 mile down the road and starts to climb to almost 220 so back to the shop I go.

Found out bottom rad hose was Luke warm at most. Popped off expansion tank cap burped it, coolant is flowing good now. Took it down the road....same thing.

Right now it has a 195 thermostat I ordered a 160 just to try. Also got a new expansion tank cap, going to try these both tomorrow.

Just a little frustrerated any help appreciated

[ORCoaster]

I think you may have to burp it several times before you get it to cool down.  I would venture a guess that you need to open the heater control and let all the air out of there too.  You have to get them to cycle the fan at the very least before you can be sure flow in all places is working.  Leave the cap loose a bit and see if that doesn't help out.  Once the system pressurizes you might be locked. 

Once it gets good and hot tighten the cap and see if it sucks any more out of the reserve.  If not you might be good to go.  You may have a stuck up thermo as well.  Unless you have been able to determine the thing works well in a pot of hot water on the stove. 

[8v-of-fury]

Upon fresh refill I always get them warm with the cap off to be sure it burps whilst warming gradually and not "PUKEEE" out the cap lol.

Also when filling it is a good idea to "back fill" the head and block via the top radiator hose down in to the head and subsequently the block. This ensures you get coolant to the back side of the thermostat, where you need it to be or it won't ever get hot there and the stat will never open.

[CRSMP5]

how is cooling system set up? vw style or zuki style?

if zuki style.. you gotta figure out a way to purdge the air.. vw had little nipple on rad to bottle for constant bleeding... zuki is like gm where the engine cycles the air better..

this topic is one that worries me on my soon to be someyear zuki build..

[audilvr]

best way to fill any coolant system. never let me down.
http://www.ntxtools.com/network-tool-warehouse/FJC-43610.html

[Smokey Eddy]

a sure and extremely easy test to ensure all your efforts right now aren't for nothing is to remove the t-stat entirely and see if you still get the over heating.
If you dont, its just a sticky t-stat. if you do... well then at least you're 5 minutes of insurance could have paid off.

after filling my vw's hundreds of times, split the rad hose at the top where it t's to the over flowm the head and the top of the rad. from here fill the head side and fill the top of the rad. eventually you'll notice the water level change on one side as you effect the other. put the hoses back together and now fill from the over flow (should only need 2 cups or so). fill it completely full (because you're going to add more).
run the car up to temp with the cap off and yopu should notice the level go down.
OR what i did was simply between the first few short trips, when you get back to the car to leave (once its cool) take the cap off and top her up.
I've faught for a long time trying to figure out why i had to keep adding more and more. there are just lots of places for bubbles to get caught.
Eventually it will all work out.

with a known working t-stat and enough liquid to complete the loop you should never over heat.

if you're still over heating you could have the timing crazy advanced. i've found that to up the heat soak a fair bit on an idi.

[Smokey Eddy]

or the moving parts are not seeing any lubrication. worn bearings/old oil/water in oil.

[CRSMP5]

eddy that does not work onon a vw.. the thermo closes off the port for bypass.. none and will overheat..

[mattrose87]

Ok so I got a new 160* thermostat and new cap put all back together got all the air out fans came on took it down the road runs freakin awesome temp stays right at 180* ,

Another quick question where is the best place to plumb oil psi gauge right now I have it on the oil filter housing 10-20 idle and only about 30 may be a bit higher when I'm going 60-65 mph I dunno what rpm is haven't got the tach hooked up yet

[8v-of-fury]

Best place for the oil gauge is on the trans side of the head. There should be a yellow (??) wire going to it. It is the last stop for oil pressure and will tell you if there is a problem there first.

FWIW, 10-15 psi at the flange is too low. However, I have read the Bentley has no idle psi number.. only a cruising number. If there is any oil pressure at the head while idling you've got enough.

[mattrose87]

So if the engine is north south there is a sending unit on the back of the head, is a oil psi reading not just oil temp

[8v-of-fury]

Oil temperature is oil temperature, oil pressure is oil pressure? I do not see how they could be the same?

Well seeing as how you are mounted in a zuki, you should be looking the engine dead on from the driver side of your rig then to get the jist of what anyone else is telling you about orientation.

It will be in the side of the head beside the coolant neck above the tranny.

[mattrose87]

Sorry may have just typed it wrong, so above the coolant neck on the back of the head (goes to the heater core) is where you are talking?.

[CRSMP5]

ok cannot run oil temp off a 8v head.. 16v yes.. 8v no.. has to have oil flow past.. the 8v design is end of head so no flow.. just pressure

rule of thumb is 18psi at 100*c at 2200rpm.. lower then that outside vw oil pressure system.. aka danger...

so filter = turbo, temp i highly suggest, so back of head for pressure above the waterneck.. you may have to brass t that for firewall room..

[R.O.R-2.0]

So if the engine is north south there is a sending unit on the back of the head, is a oil psi reading not just oil temp

there was never a oil temp sender located in the head anyways.. only a low oil pressure switch..

i would still install my new oil pressure sender in the back of the head.. its the lowest pressure in the whole engine.