Fitting new underfloor heater pipes.

One of the most worrying aspects of the MGF is a sudden loss of radiator coolant, the subsequent engine overheating and possibility of head gasket failure (HGF). Obviously there can be other causes for coolant loss, so it is always worth conducting periodic checks on all the hoses and pipes and make a habit of checking the coolant expansion tank every time you open the boot.

However, the early MGF's are particularly prone to corrosion failure of the underfloor coolant pipes, partially due to design and now to age. The pipes are steel, and run from just behind the radiator to just in front of the engine, most of it in a very exposed area. Whilst the correct mix of anti-freeze to water offers significant internal protection, the outside is vulnerable to significant rusting, as can be seen from the condition of the pipes on my 1996 model.

Click to enlarge Click to enlarge The rusting can be deceptive. Mine looked as they might fail at any time. However, once off the vehicle, it took some reasonable effort to pierce the pipes using a screwdriver and hammer ! But do not assume that yours are the same. If they look bad - replace them.

  • Replacement pipes can be obtained from Rover or Mike Satur, who offers aluminium pipes, which reduce the tendency to corrode.

    Click to enlarge Click to enlarge I chose the pipes from Mike Satur. They come with the required fixing bolts and spacers, and you can order stainless steel hose clips at the same time. Pictures courtesy of Mike Satur

  • Before you start, be aware that the refilling and bleeding of the coolant system is critical and requires care to ensure that all the air is removed and that the coolant is circulating properly. Further below I have outlined the stages for refilling and bleeding the system. It is also well covered on other web sites, so if you need details of where the various bleed screws are and hints on the bleeding process, have a look at...........

    Dieter's Site
    HGF diagnosis

    Click to enlarge Click to enlarge To make access relatively easy, you need to either lift the car on a full hydraulic ramp, or support it on axle stands / car ramps so that the car is level with all 4 wheels off the ground.

  • Ensure the internal heater temperature controls are turned to FULL ON to ensure that the system drains and refills completely.
  • Remove the expansion tank filler cap.
  • You will need a bowl or container large enough to hold 10.5 litres of coolant as you drain the system. Undo the two clips at the rear / engine end of the pipes and allow the coolant to drain. It will gush out quite quickly once you pull the rubber hoses off the pipes, so an old kitchen washing-up bowl is ideal. Having allowed the initial rush of coolant to drain, open the bleed screws on the top of the radiator and at the back of the heater, to allow the remaining coolant to freely drain.
  • When the system is fully drained, remove the clips and hoses from the opposite end of the pipes.

    Click to enlarge The underbelly panel is held in place by 22 bolts. Note that the panel has slots instead of holes for 2 of these bolts on the front leading edge of the panel. These particular bolts should only be loosened off rather than fully removed, thereby allowing for easy partial support of the plate when refitting it.

    Click to enlarge Loosen these two off about 3 mm, leaving at least one bolt on the opposite side tight, but remove all the other bolts. You can then undo this one remaining bolt, easily supporting the plate as you do, and then slide the plate forward off the other two slackened bolts. Leave these two bolts as they are, so that the reversed procedure can be followed when refitting the plate.

  • Now cut the plastic tie-wraps that hold the starter motor/battery cable.
  • Undo the 2 bolts that hold the pipe assembly in place, and remove.
  • The Mike Satur pipe assembly is slighty different in design to the original pipes, in so much as the former uses spacer tubes on the fixing bolts. Fit the bolts through the coolant pipe support brackets, slip the spacer tubes over the bolts, present to the car and screw in the bolts. Do not fully tighten until you are sure that the pipes, bolts and spacer tubes are correctly lined up.
  • Fit the four stainless steel hose clips over the hoses and push the holes onto the pipes. Try to avoid having the clip bolts being too prominent since they would be likely to snag on anything passing under the car, but set them slightly off centre so they are easy to tighten if need be.
  • Refit the underbelly panel by sliding it first onto the 2 bolts that were left in place, and then refit the other 20 bolts. Do not tighten them up until all are fitted. Then torque them to 22Nm.
  • Tie-wrap the starter motor/battery cable back in place, and you are ready to refill with coolant.
  • Now make sure you are aware of the full process of refilling and bleeding (see below and web links above).

    Refill and bleed.

    1. Remove the bleed screw from the radiator and open the heater bleed nipple. See Dieter's Site if you are not sure where they are.
    2. Fill the system with coolant. Keep the expansion tank filled to prevent air being sucked into the system. The full system has a capacity of 10.5 litres, but since it's a 50/50 mix, you will only need 5.25 litres of Anti-Freeze. Check in your Manual or with your Rover Dealer which Anti-Freeze is appropriate for you car - it is important not to mix them.
    3. When a constant flow of coolant, with no air bubbles, is flowing from both bleed screw holes, refit and tighten ( radiator 5Nm, heater 7Nm ) both bleed screws.
    4. Fully fill the expansion tank, fit the cap and start the engine. Make sure the air conditioning, if fitted, is OFF
    5. Let it run until the radiator cooling fan starts.
    6. Check that no leaks occur and that the heater is working. If there is no heat coming from the heater, you will need to perform an additional bleed.
    7. Turn the engine off, allow to cool, check the level of coolant in the expansion tank, and top up to the MAX mark if required
    8. Remove the access panel to the engine compartment and allow the engine to cool.
    9. Remove the inlet air hose from the throttle housing by first removing the retaining clip.
    10. Ensure the expansion tank is topped up.
    11. Remove the bleed screw from the radiator return rail. When a constant flow of coolant is seen coming from the bleed screw hole, refit and tighten the bleed screw to 9Nm.
      NOTE: I had great difficulty in getting any flow from this bleed screw, until I jacked up the rear end of the car on ramps and ran the engine for a short burst. This may not be ideal, so as a further precaution I lowered the vehicle, rechecked the other bleed screws. Having been convinced that all the air had been removed, I re-ran the engine until the radiator fan cut in, allowed the engine to cool, and refilled the expansion tank up to the MAX mark.
    12. Refit the inlet hose and clip to the throttle housing.
    13. Refit engine compartment access panel.
    14. Recheck the coolant level and top up to MAX level if required.

      Keep checking the coolant level on a daily basis for a while, just to make sure you have no leaks