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hello,
got some serious questions about overheating in my 86.
i'm getting concerned about blowing a head gasket.
the oil gauge has been showing rising temps in the oil. my 92 doesn't show higher oil temps on the gauge under the same conditions.
first, the engine did get pretty hot for hours during the rita evacuation here in houston. i don't know if that had any effect on what's going on now.
i've got a used nissens 3 row rad last year--fine shape, regular fan & an electric puller fan, 1.5 yo volvo water pump, no coolant loss, all known vac hoses checked/ replaced, intake manifold replaced, tune up, t stat pretty new, pretty new hoses both rad & heater hoses, 1-2 yo oil temp sender, etc. i looked at the a/c condenser fins, some fins are bent, but really nothing much to block the air flow. the crank pulley is getting old but there's no indication that it's slipping.
but the oil temp still rise and the weather is pretty decent now (72 deg, 56% humidity). i have an LED in the car hooked up to the rad fan switch, and the red light is turning on showing elevated water temps during mild days.
the water temp gauge in the cluster is not moving up though--still a little above halfway as usual.
i'm thinking it's carbon buildup in the head, and i'm thinking of buying a heavy duty aisin fan clutch.
and it's not even Texas hot, yet.
Questions:
1) will carbon buildup in the head do this?
2) fan clutch maybe going out?? if so, then what about the 20 amp Perma cool fan?? seems to be blowing pretty strong.
3) get a head job at a shop?
4) change the viscocity of the oil??--i'm changing over to sae20-50 at next oil change.
need some help on this one, and thanks as always.
byron golden
86 245
92 245
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have you considered that the electrical system may be affecting the readings?
how is the wiring? if you get to an overcharge state, or if there is a short that appears at running temperature you will chase your tail and never get a real feel for the running condition.
the gauges can act a bit like voltmeters - does the fuel gauge change to higher than it should also? if so, it is an electrical situation.
--
Stef (scotia blue 81 245 B21A SU M46 3.91 350000km)
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stef,
that might be a real problem--when i turn on the parking/headlights, 3 of the gauges increase a little. i believe i've grounded 3 of them, including the oil temp gauge all together.
i need to check for proper grounding.
thanks & regards,
byron
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If worried about head gasket, go to NAPA and pick up a combustion gas test kit ( comes with little tube that fits in expansion tank opening andfil with blue fluid, if it changes colour you have leak to the coolant, if not, you're OK. then run a compression test.
Chances are though you just need a new fan clutch and to clean and straighten your radiator fins.Those Tropical fan clutches work nicely in hot climate
--
-------Robert, '93 940t, '90 240 wagon, '84 240 diesel (she's sick) , '80 245 diesel, '86 740 GLE turbo diesel, '92 Ford F350 diesel dually
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Robert,
thanks for your reply. if i don't have a grounding issue, i think i'll go ahead and get the tropical clutch.
meanwhile, i'll get that kit and check. i haven't noticed any coolant leaking from anywhere, but this will detect the gases at least.
hopefully it's just the clutch.
regards,
byron
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Hi Byron -
I used 20W-50 for years, and now I have changed. Never noticed any oil-related problems, but here's my thinking:
The oil heats quickly, so the viscosity will move away from the low number quickly. Low end (5W, e.g.) gives quicker pump-up into bearings and top end. Getting to the higher end is where the pay-off is, IMHO.
The wider the spread between the numbers, the more additives are needed, and the proportion of oil to additives changes. Lower spread = more oil.
I have 5W-40 in the 965 now, and the change from 10W-30 ended the morning start clatter. I am seriously considering changing to 5W-30 next change.
Now, about the idea that the head gasket is blown. My 1979 245DL (now in Volvo Valhalla) blew one after a severe overheating episode. One indication is the gushing up of coolant upon first morning start with the coolant tank cap off.
When starting first up in the morning, open the hood, remove the coolant cap, and position yourself to where you can see the coolant tank while you start the engine. If the coolant wells up and out of the tank, the gasket is breached somewhere. Combustion/compression pressure is getting into the cooling system, thus the the gushing up of coolant. It's possible that when the engine is fully warmed up the heat expansion could close off a small breach.
Surprisingly enough, I never noticed any coolant loss with the cap installed, and there seemed to be no oil in the coolant, either. The temp gauge went up to one red-width below the red, but never any higher. The engine ran OK.
Now that I have read this BB several years, I would not shy away from a head repair. Back when my 1979 blew, I would not have touched the job.
Good Luck,
Bob
:>)
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Bob,
about the viscocity, makes sense. i didn't think about the additives, either. i'll try the higher weight oil just one time to see about the heating. i'm thinking about the heavy duty clutch too.
i'm going to take the temp comp board off and do a bypass for an accurate temp reading.
I need to check proper grounding too, because when i turn the lights on (parking & headlights), 3 of the gauges jump a little and all are grounded together.
regards,
byron
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Hi Bob,
great to hear from you and thanks for your sage reply.
i'll check on the coolant bottle tomorrow morning.
i was thinking of doing a head job as preventive maintenance.
what was the conditions under which you blew your head gasket?
i'm trying to avoid Thor's hammer!
i'm busy next week, but maybe late april or in may we houston area volvo guys can get together somewhere on a saturday.
regards,
byron
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