I have a 1968 MGB that seems to have a lot of trouble keeping cool in
traffic. Today was the first nice day we've had in ages, with a high
in the low 70's. Driving back to work at noon I got stuck in a backup
and, true to form, the temperature needle started heading up toward H.
By the time I got away from the problem (about 10 minutes of sitting)
it was about 7/8 of the way to H (but still clearly away from the
solid mark at the end of the gauge). As soon as the car got moving
again it quickly got back to the 3/4 mark and continued heading to N
as I got to work.
The engine has about 2K on a new rebuild and is running well (if
anything a bit rich). I backflushed the radiator at the rebuild and it
seemed to flow fine. It has an oil cooler. There's plenty of coolant
and I've retrofitted an overflow bottle. I'm pretty sure it's got a
12lb cap, but I recall some ambiguity between 12 and 6 lbs for a 1968
B. During cooler weather (50F) the temp gage sits nicely at N, so I
assume the thermostat is opening on cue. The overheating in traffic,
by the way, is not new since the rebuild. It has always given me
problems in traffic. On the highway it will creep up in hot (>80)
weather, but will always stabilize well before the halfway mark
between N and H.
First, is this normal behavior? Should I be looking for a new
radiator? Is a lower temp thermostat much help? At what point in the
needle's travel toward H should I get nervous and pull over? Are
regular trips of the gauge toward H normal and not to be worried
about?
If the problem is inherent, I'm thinking that switching to an electric
fan might be the way to go. What electric systems work well in MGB's?
What CFM rating is necessary? Should the belt driven fan be removed?
Should the fans be mounted in front of or in back of the radiator?
Pulling or pushing air? JC Whitney seems to have a variety of generic
options and Moss also sells one. Is the fan sold by Moss a more
expensive version of the JC Whitney fans? I assume the electric fans
current draw can be tolerated without much difficulty by the B's
charging system.
I'm surprised that there is no cooling system FAQ on the SOL Tech
page. This topic seems to come up at least as often as SU fuel pumps
although we appear to be on a winter cooling system hiatus.
Unfortunately, I haven't bothered to archive the cooling system wisdom
that have been through my mail box.
Thanks in advance for any suggestions.
Jim
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| Jim Feyrer | University of Wisconsin - Milwaukee |
| jfeyrer@csd.uwm.edu | Mechanical Engineering Department |
| (414) 229-3716 - voice | PO Box 784 |
| (414) 229-6958 - fax | Milwaukee, WI 53201 |
|