Bleeding the radiator system

[Peter Delaney]

Huw, some simple ideas that I have used with great success :

- Small 1/4-turn brass tap installed in the side of the temp sensor mount at the front/right of the inlet manifold (highest point for water in the engine). A clear plastic tube from the tap, down to just below the chassis rail.

- A similar brass tap installed as high as possible on one of the radiator side tanks (highest point for water at the front of the car). A temporary clear plastic tube to a catch tank on the ground.

- Preferably, a similar tap in the highest heater hose under the dash. (highest point for water in the middle of the car). A temporary clear plastic tube to a catch tank on the ground. (I have managed ok without this one as yet - I just have to have heater valve open & the air seems to flush out ok).

- Filling : I just close the brass taps, & then siphon coolant from a container sitting on the roof, down into the header tube/tank till it is full (the slow filling from a small bore tube helps keep air bubbles out). The header tube/tank top is about 1" higher than the temp sensor mount, so it is the highest water point in the whole system.

Once the header tube/tank is full, I just open the brass taps one at a time & watch the bubbles coming out the clear plastic tubes (being careful to not let the water level in the header tube/tank get low enough to let air into the main pipe to the thermo housing) - open tap for about 3-5sec, then shut it & top up the header. Two or three rounds of this activity on each tap usually sees all the trapped air at these points gone.

Then I run the engine for a few minutes to move any other trapped air to the high points (& to build up a bit of pressure), then repeat the tap opening / top-up procedure.

The beauty of the little taps & tubes is that you can manually bleed the system anytime - even with a very hot engine - no risk of 3rd degree burns !

Having had some nasty experiences with air/steam in the system & blowing a main hose in the bad old days, I am a bit anal about the whole bleeding issue - hence the taps/tubes (& that fact that I do a very quick bleed from each tap (hot engine & header tube pressure cap in place) every couple of months (and check that the overflow tank is at least half full) - just to be sure !

The initial filling & bleeding process only takes about half an hour, & the hot quick-checks about 5 mins.

PS : Definititely follow Burns' & Ricky's advice re connecting the 2 rear water ports to the thermo housing.

I hope that this helps a bit.

Kind Regards,

Peter D.

 

[Huw Peplow]

thanks for all these good techniques .

having achieved a full bleed out today and run the engine it reached a max of 105 in a standing situation .If moving would have expected it to be about 90 so all seems in order

Sorry not quite ,decided to check the oil ,put finger into rocker cover and a trace of white GUNK! obviously not got the inlet manifold on correctly so have the great job of warm the oil ,dump it out ,rocker covers off ,inlet manifold off and clean up and replace.

Does any one have torque setting and tightening sequence for the inlet manifold of a ford 302?

on manifold removal I noticed a bit of broken off thread from the engine block so this could be a little more serious than first appears .Might test my ability with the old helicoils or top hats

*********!!!!

 

[Neal]

18-20 ft lbs
Cross pattern starting mid manifold working out and then to center.

 

[Huw Peplow]

have done that neil to those spec .Unfortuneatley the 2 bolts on the lt bank at position 2 and5 (if you know what i mean) wont torque up .When they were first un done some ali thread came out with them so I will either have to drill and over tap them with a larger bolt or heli coil them. Must have been over torqued originally by manufacturer

having gone metric in uk what size bolts are those in the inlet manifold as I will need the coresponding heli coil

Have cleaned out top half of engine ,any suggestions on cleaning out the rest with out removing the engine and sump pan!!! Its amazing the amount of mess made in a few seconds as I was just warming her up to open the thermostat to help bleed the system

 

[Howard Jones]

We were just discussing the inlet manifold bolts issue here a couple of weeks ago. IF you have aluminum heads I would stud them for the inlet manifold. The problem is it seams to take very little torque to strip the threads in the heads. Part of the problem is short bolts. Replacement/ upgrade aluminum heads sometime have thicker bosses around the bolt holes and this causes the short bolt problem.

If you don't stud aluminum heads for the intake then I would be VERY careful and tighten the bolts down by hand. Make sure the bolts you use are long enough to use all the threads in the head less a little clearance at the bottom of the hole.

If you have steel heads, go ahead and torque them as above. You should look up the torque sequence in a Ford book.

 

[Huw Peplow]

Totally agree with that. The use of studs would be a much better option. Was speaking to an old garage friend who was very informative about the torque of the bolts.

The regieme was torque from centre out in a cross/diagonal pattern to 16-20 lb/ft then repeat increasing torque to23-25 lb/ft so after the helicoils (5/16 unc) that will be done.

Have decided to totally remove the engine as the oil on removal was pretty contaminated with water .Have cleaned out the top half of the engine which wasnt to bad

A marie engineer said that due to the way an engine breathes if a minor amount of water is left it will eventually evapourate from the oil areas of the engine. Any comments!

Does any one recognise the inlet manifold gasket on my roush 342 as living here in the uk there is little information on the different ones.A part number would be helpful .Need to obtain a set very quickly as the car is due at a show on the 17th!!

Off topic just got ford gt badge from the new rf ,Its absolutley fabulous

 

[Jac Mac]

Hugh,

Most Alloy heads now come with revised ( LOWER ) torque values for the intake bolts, DO NOT attempt to use the factory 25/30 ft lb settings with alloy heads. Also choose the valley corks thickness by trial fitting manifold without them to measure the thickness reqd ( simply set manifold in position with new gaskets( dont tighten ) and measure valley gap to choose cork thickness.

Sorry cannot help with p/n for gaskets, but they appear to be a universal type that can accomodate all three basic variants- ie; early 289/302- 351w- and later 302 as the end water holes have extra raised beads to suit the extra bolt of the 351w etc.

Ensure you get as much water as possible out of the motor, even fill with some straight 30w and remove the dist to hand prime/flush the oil system before refilling with the correct grade of oil, dont forget to change the filter.

Jac Mac