Coolant hose flaten

[sicj]

So this is a strange problem that I can't figure out...

bought my friends 92 coupe with a DE in it. The car does not overheat, rad is full of coolant as well as the overflow.

turn the engine off after a drive, the coolant goes back into the overflow. After that there is a boiling/gurgling sound coming from the top hose and the top hose slowly gets vacuumed flat as the sound fades away. the hose is FLAT, this also sometimes happens to both the upper and lower hoses, but not always. It sometimes also happens while the car is running.

I've had the car for a week-and-a-half and this has happened since I bought it. Car has never overheated or shown signs that it was.

release the rad cap and of course everything expands back to normal.

what the hell could be causing this? it's like I have a vacuum inside the coolant system sucking the hoses down.

[S133P3R]

bad radiator cap?

[sicj]

bad cap, I would overheat

also that vacuum that's occuring wouldn't be able to happen with a leaking cap.

once I release the cap the hoses expand back to normal. that means that cap holds pressure (and vacuum in my case)

[S133P3R]

stumped me. thermostat installed? also, is a max filled overflow a good thing?

[sicj]

overflow filled, means to the fill line....

thermo's in and works

[S133P3R]

?

[Warped161]

Sounds like an air bubble trapped in the coolant system, do the de's have the same little venting screw as the sohc do? If so it should be on the manifold near the thermostat.

[S133P3R]

i think the bleeder is the same spot on SOHC and DOHC. on top of the intake manifold, closest to the from bumper. i think its a 10mm bolt and it has a small warning sticker next to it.

[Azrial]

Either it's a really strong vacuum or the hoses sound like they are shot. I would look into new hoses it may not fix the problem but they sound kind of bad off if they are collapsing

[NISMO24096]

HA HA HA HA you are having the same problem that I had with mine and no one could figure it out either...but its a really simple thing to fix...just check these few things and your problems will be solved..1) take the hose off the overflow tank that runs to the radiator..I will bet you money its clogged with slime and such...either replace it or take a close hanger to it like i did mine.. then test it to make sure it is free flowing..

2) check where the hose connects to the overflow tank and the radiator, make sure there is no blockage at either point...

3) replace everything and thank me later....ps good luck and I hope this solves your problem, I know it worked for me....

[djmatt79]

get a new hose... get a full coolant flush... then bleed the system

[NISMO24096]

hey SICJ Did you ever get your problem fixed????

[airman86]

think about it...when you have a boiling liquid and lots of steam, once it cools down the volume decreases significantly. i would vote the thermostat's not closing all the way like it should, but i couldn't tell you for sure. the same thing happened on my jeep i owned several years ago, replaced the thermostat and that fixed the issue.

[greencar]

I am going to say bad radiator cap on this one.

Get one and try it out, or borrow a friends.

-Dan

[cleopp3]

had the same exact problem, system needs to be drained and run some radiator flush just be careful cuz that stuff can eat away at gaskets and leave u with a leak, most def do the water pump while your at it. tremendously helped out. plus cant go wrong running new CLEAN fluids.

[s13dorifta]

try checking the Radiator hoses they commonly have a reinforcing spring inside that helps prevent radiator hoses from collapsing. If this reinforcing spring is faulty or missing, the hose may collapse when there is a vacuum in the cooling system. Another cause could be a faulty radiator cap. A radiator cap works to maintain a constant pressure in the cooling system. As the antifreeze mixture begins to cool after engine shutdown, a vacuum is created. If the pressure cap doesn't equalize this pressure, a radiator hose can collapse. The small vacuum valve in the radiator cap may not be working properly.so try changing the radiator cap.

[1KleenS13]

I had this problem when I got a new overflow bottle. Turned out to be a clogged line from the overflow to the rad. Do your hoses build alot of psi when the car is running?