collapsing top hose

[3bears]

so maybe normal and I have never noticed.
Bought this neglected 4runner about 3 months ago. It was beat. I put in a coil, plugs, wires, pcv,flushed the cooling system, new aisian red, NAPA radiator cap, the overflow hose ( plain vac hose). Air and fuel fiters. Cleaned the maf and throttle body. Still throws code for the rear o2 sensor which I have not yet done. At the time I did a compression check, a leak down, and one of those chemical testers for the radiator to check for exhaust gas....all good. I did burp the system several times, have one of those extended funnels too for burping.

I noticed the other day that when cold, the top hose is collpased , like sucked dry. Yet the radiator is full and over the past 1500 or so miles have maybe lost 1/4 to 1/2 inch out of resavoir. It is an after market radiator hose ( not by me) it is due for a timing belt in about 12k and I will do the water pump. Temps stay fine. NO coolant on ground or around bottom of engine. NO oil loss, no condensation in oil or under fill cap, no smoke or sweet smell to exhaust on start up. When I open the cap the hose expands to normal, fluid level is at top of radiator. No idea on age of radiator, but its not original. No water in trans fluid.

Maybe this is normal for these rigs and over all the years just never noticed. Maybe its the cheap aftermarket radiator hose, or the radiator cap I put on.
Now I got this sick feeling ive got a head gasket starting to go, or a cracked head or something. At 265k.Maybe im over thinking this.

Ideas ?

 

[ej86923]

My top hose is rather firm shortly after startup. I noticed this because I just did a flush and bleed recently.
Did you make sure the heat was on when you were burping it. Maybe air in the heater core.
Even with the no spill radiator funnel I park it on an incline to make sure the air comes up when bleeding.

 

[3bears]

My top hose is rather firm shortly after startup. I noticed this because I just did a flush and bleed recently.
Did you make sure the heat was on when you were burping it. Maybe air in the heater core.
Even with the no spill radiator funnel I park it on an incline to make sure the air comes up when bleeding.

mine firms up right after I start it, yes I had on ramps and both heaters on, and with the few months driving, I think it would have self burped any air that might have still been in it. Maybe its just a cheap uppper hose that really sucks in...maybe it is nothing. But just ordered a new upper hose ( toyota)

 

[R Marra]

Is it possible that your thermostat is stuck in the closed position

 

[3bears]

Is it possible that your thermostat is stuck in the closed position

wouldnt it overheat ? But its a possibility, this has been one neglected old girl and every repair that has been done in the past by previous owner used the cheapest aftermarket crap you could find.

 

[alumarine]

Your rad cap might be defective.
That's a symptom.

 

[phattyduck]

Get an OEM cap, and make sure the feed/suction line to the overflow bottle flows easily.

There should be zero 'vacuum' in the cooling system - the radiator cap should allow for the overflow tank to suck fluid back in if there is any negative pressure in there.

-Charlie

 

[LittleCaesar]

New OEM radiator cap should work as other have stated.

Your NAPA experience mirrors mine. Once the gold standard for aftermarket parts replacement, they have followed in the footsteps of the other big name auto parts chains in stocking as much PRC junk now as possible. Still like the Carlyle tool brand though.....

 

[HiLife]

The coolant is stuck somewhere flowing back into the radiator from the reservoir tank as the engine cools. Could be a plugged line or a defective return valve on the radiator cap.

 

[Devbot]

Rad cap. Cheap ones from vatozone or O'Reilly's will do it without fail. You may even notice it come and go, if I remember correctly it's because the valve in the cap gets stuck.

 

[3bears]

well at least none of you are saying cracked head or blown head gasket....thanks.

guess ill hit up the dealer....i dislike them...they know they are the only dealer for near 260+ miles...when I needed it 3 months ago they were like $25 and napa....recomended on this forum for cap....was only 11 and the project was already kicking my butt.... when I need genuine toyota I try to order on line...if I have a big order and time to wait...shippping to me is a killer for price and time. All shipping is a killer..(.a dobinson lift kit is over 400 just in shipping) and places that say free shipping....read the small print....and amazon prime is usually about 10 days to 2 weeks this time of year...summer just a week.
the local toyota dealer is about 15% to 20% higher if not more than posted toyota list prices.... had to get a gas cap and it was 37.. ( well 36+)...they know they have a locked market.. and the next dealer is the same company...... I guess the parts have to be brought in by reindeer and sleds . If you have to order from dealer, expect a 2 week wait unless you want to pay air freight and "handling"
ok enough complaining ( thats a nice word to what I think)

 

[nissanh]

OEM radiator cap and clean the overflow flexible tube, radiator overflow outlet and cap and hose in the reservoir.

 

[19963.4lsr5]

Is it sucked flat before you start the engine or after it’s running?

All 3 3rd gens I bought had broken OEM rad caps. Napa’s never caused me any problems.

Cold engine wise you should be able to squeeze the upper hose and hear coolant pushing into the overflow/expansion tank.

Below is a stretch...
How old is the T-Stat? That upper hose is on the discharge side of the water pump. The only way I can see it sucking flat is from a low pressure in the upper hose area as the coolant is circulating through the bypass tube under the intake through the heater core. If the jiggle valve in the t-stat is working correctly it should allow the pressure to equalize between the top and bottom of the block until the stat starts to open.


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[alumarine]

I installed a Motorad T-36 Rad Cap five years ago and no problems.

 

[3bears]

Is it sucked flat before you start the engine or after it’s running?

All 3 3rd gens I bought had broken OEM rad caps. Napa’s never caused me any problems.

Cold engine wise you should be able to squeeze the upper hose and hear coolant pushing into the overflow/expansion tank.

Below is a stretch...
How old is the T-Stat? That upper hose is on the discharge side of the water pump. The only way I can see it sucking flat is from a low pressure in the upper hose area as the coolant is circulating through the bypass tube under the intake through the heater core. If the jiggle valve in the t-stat is working correctly it should allow the pressure to equalize between the top and bottom of the block until the stat starts to open.


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I have no idea on how old the thermostat is, just bought this 3 months ago, and has a timing belt sticker good for another 15k maybe, but Im gonna do the complete belt/pump etc this summer. Seems like everything I have opened up on this rig has been cheap poor repairs in the past, like single electrode ac/delco plugs were in it, air filter so dirty and plugged.

the hose is collapsed when not running and cold.... if you open the cap it expands... or as soon as you start it.
many say the napa rad caps are good, maybe I just got a bad one.

 

[3bears]

can a rad cap with a 3psi difference make a difference. Reason I ask is I just looked at the rad cap and it says 16psi......yet I have seen in print that we should be running a 13psi cap

wonder if Napa sold me the wrong one, cause i just went to thier site and it also lists 13psi for the yota.

 

[19963.4lsr5]

can a rad cap with a 3psi difference make a difference. Reason I ask is I just looked at the rad cap and it says 16psi......yet I have seen in print that we should be running a 13psi cap

wonder if Napa sold me the wrong one, cause i just went to thier site and it also lists 13psi for the yota.

Is there a black center in the bottom of the cap? It needs to be a vented cap.

I can walk out and take a picture of my napa cap. Either the cap is bad or it’s the wrong one or your line or inlet at the tank is plugged with dirt.

Balkamp BK 7031728 13psi/.9bar

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[alumarine]

can a rad cap with a 3psi difference make a difference. Reason I ask is I just looked at the rad cap and it says 16psi......yet I have seen in print that we should be running a 13psi cap

wonder if Napa sold me the wrong one, cause i just went to thier site and it also lists 13psi for the yota.

I'm not sure what too high a pressure cap would do but you're right that it should be 13psi.

 

[phattyduck]

I'm not sure what too high a pressure cap would do but you're right that it should be 13psi.

It puts more pressure on the hoses, etc. and may lead to leaks. Otherwise, it is all good - it also increases the temperature at which the cooling system will boil, which helps keep the motor safe when pushed hard.

-Charlie

 

[3bears]

got a rad cap at dealer, no difference after engine cooled