Rb26 Temp Rising And Falling Rapidly

[SCRMER]

I'd pull off waterpump and check for shenanigans before pulling engine

Already on our 2nd pump and 3rd thermostat! No improvement

[GTRPSI]

Was the engine recently rebuilt and it started from the moment the new engine was in?

[SCRMER]

Yeah it was. I havent actually taken the car back from the workshop since being rebuilt. Looks like a problem since the car has been first started as we havent really put any kms on it

[Hadouken]

Maybe it's time to tear it down if you are 10000% sure you got all the air out

How did you say you bled it?

[SCRMER]

Maybe it's time to tear it down if you are 10000% sure you got all the air out

How did you say you bled it?

Yep that's the plan it looks like

Tried a few different methods.

- let it idle and keep the revs around 3 to draw in water into the motor.

- Kept the heater on all the time

- after a few mins, switch it off and let it cool down

- Opened the bleeder valve with the car off and with the car on until steady streams of fluid came out. Not once were there bubbles or broken stream. Water seemed to be in the head at all times from the get go

- Tried jacking the front up as high as we could so the radiator was higher than the motor and repeated the processes.

- tried having a bottle cut open with fluid in it, sitting in the radiator as we were idling and revving to see if it would suck more in. kept sucking in a lot and when it finally didnt want anymore, it stopped.

- Tried a method with the radiator cap on and the car on and letting air out of the bleeder valve, which none came out.

- Drove the car down the street, around a few corners and up a few hills to just see if we could push any air pockets out

- Used a vacuum machine to suck any air out, nothing really did

- had the car running for a few mins, stopped it, let it cool, tried letting air out, and repeated that process many times over a few days incase things needed to settle.

Nothing we did made a dent in the issue.

[Hadouken]

So with this temperature change. Was it present with the coke bottle in the radiator?

How is your overflow bottle reacting?

[SCRMER]

Yep it was, it would get worse and better as the temp rapidly cooled and threw out the hot water. As the motor got a burst of cooler water, the hot water coming out would cause disruption in the water in the bottle and move it around a bit

To be honest didnt check the overflow so i dont know

[Ben C34]

Did you have the cap open, with a funnel or bottle cut open pushed into filler neck, car running and undo bleed nipples? While adding coolant.

[SCRMER]

Did you have the cap open, with a funnel or bottle cut open pushed into filler neck, car running and undo bleed nipples? While adding coolant.

Exactly what we did. Def sucked in some fluid in. But just a steady stream coming out of the bleeder

[GTRPSI]

Ok this might sound really, really stupid but its why i asked if its been freshly rebuilt.

Pull your thermostat back out, get a mirror and torch and under the thermostat they should have replaced (if they pulled out all your welsh plugs) a small welsh plug inside the block, its sits in the block under the thermostat, from memory its around 20mm big (guessing).

There is a very real possibility that they may have knocked them all out to clean the block and forgotten there was one in there, its easy to miss for someone who does not know RB's or got the apprentice to knock them all in.

Yeah i know its a pain in the butt, but you never know......

[Hadouken]

Did you do some grout filling on this block?

[GTRPSI]

Your looking to see if this plug was put back in, its at the top center of the crappy pic i took, way down under the thermostat, behind in a second casting.

[SCRMER]

He is sure he put them in but was questioning to ensure that he did. Could be another reason he wants to pull the motor apart

But the above helps. It is something new to investigate at least! Thanks!

[GTRPSI]

Just remember there are 2 open holes and a third one that the plug goes into.

One big one that the thermostat outside sits in with the casing over it held down by the 3 thermostat cover bolts.

One that the thermostat end rear/base sits over which is left open and is slightly bigger (by only a few mm) than the welsh plug under it.

Then the third hole which is the deepest and smallest, that one gets the welsh plug.....

Edited August 6, 2015 by GTRPSI

[SCRMER]

That has been check and everything is fine from that end apparently. Looks like a motor out job from here on in.

Will let all know the outcome

[Hadouken]

i am looking forward to the outcome of this.

[SCRMER]

You and me both. I just want to drive the car!

[thewayweroll]

We just had 2 Koyo radiators fail from new in a 34 ,didnt have as severe issues as you ,but still did all the changes and checks you did as we didnt think it was a radiator issue .Both seemed to be partially blocked and both split and leaked with in 2 hours of driving ,put a new Blitz in and happy days ?

[SCRMER]

Did you have similar issues with temps rising and falling or was it just a constant rise and not coming back down?

it's interesting. Few other standard gtrs we were comparing with over the last week. The standard ones you could start up, drive out of the driveway and see it gained 10 degrees and heat would just slowly rise every min the car was on. Mine, well it just stayed cold for so much longer, temps wont budge, then all of a sudden a lots of heat!

Pulled the motor out of the car on Saturday. Going to pull the head off it hopefully today and get a good look at what is going on. Hopefully it's something little that has been missed!

[thewayweroll]

it was rising and falling but not rapidly like yours is , I believe they were partially blocked or something , then they split and leaked