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The heater doesn't' appear to be working on my tr7 v8. The levers appear ok - could it be airlocked or anything lime that ?

The car is running up to heat, so I'm sure it isn't the thermostat.

Ideas chaps ?

Brian

I've had my Grinnall TR7V8 3 years. My heater has always been pathetic, and have a feeling it may be related to somewhat erratic temperature behaviour, which I've messed about with only moderate success.
Very interested to hear other TR7V8 experiences.
Al

The controls levers may move OK, but that doesn't mean the cables they're meat to move are doing anything useful, could be something as simple as a retaing clip has fallen off, a broken cable or it could be that the heater valve is buggered.

Unless bypassed, the heater matrix receives a continuous flow of coolant from the engine. It's possible that the matrix is full of crud and not much is flowing through it. Check the hoses that feed it from the rear of the engine when it's next up to temperature. You may have to remove the fresh air plenum under the bonnet to do this. If one of them is much colder than the other, or they're both cold then I'd expect a blockage. The heater matrix should be toasty hot with a V8 feeding it.

Removing the matrix is a horrible job, it was a complete dashboard out and heater box dismantle and reassemble operation for me. The mild steel pipes and seals that connect to the matrix rust and perish respectively causing leaks. Searching the forum wil find several threads.

As per Cobber, the heater box control rod levers can become loose and lose some of their movement. Here's some pictures of what they look like behind the dashboard. The heater box is upside down on the bench.





Adam

Unless you did the engine instillation yourself, anything could have been done to the thing. Our 8 has a 3 way cock in the plumbing between the engine & the heater, reasonably well hidden. We had no indication where it should be set to pass water to the heater. Here in sunny Queensland we wanted to stop it.

Those heater controls are a work of the devil. A couple of mine fell off the under dash unit about yearly, but you couldn't pull them off safely under there. You needed 2 people to be sure you were putting them on right, when ass up, head down under the steering wheel. It was a few years before them being off & intelligent help available coincided & I could Loctite them on.

Check for hidden aftermarket controls, & back flush your matrix if there are none. Be reasonably gentle, I had one where green water, [coolant] blew out of the ventilation vents, when the fan was switched on.

Hasbeen

Probably a blocked matrix. my heater throws out plenty of heat (albeit an A/C heater but I think the difference would be basically the on/off control for hot water passage and not have any difference in the amount of heat it can put out). A friend's Sprint conversion puts out no heat but I think that's a blocked matrix as well. When I had mine out I soaked CLR in it then flushed it out with a hose.

I had the exact symptoms you describe. Turned out to be a blocked heater core and the wrong thermostat - both things previously mentioned. I didn't figure out the thermostat until I had taken the matrix out and rebuilt it. I replaced the stock heater core with one from a VW. (The VW one cost me about CAD60 instead of upwards of CAD150.) Once that was in the car, it became apparent that the thermostat was too low. Now I get lots of heat.

Lots of people put a low temp thermostat in because they have overheating problems rather than fix the more expensive "problem" which is a clean, unblocked radiator and inadvertently put in the wrong type (shape) because they are commonly available. With this low temp thermostat they can't get the temp out of the car. A number of years ago the thermostat in my Integra failed (they fail open which is why they are spring loaded for safety sake) and I could get zero heat out of the heater (it was in winter were temps can fall to 1C to 4C). The cooling is very efficient in the car and the temp gage would barely move. New thermostat and heating was back to normal so the right range will make a difference (as well as right type).

I think i will test the thermostat, then give the sustem a full flush, then fill it with the correct fluid - out of interest, being lazy, what spec is antofreeze

Brian

While you have it out make sure the PO didn't replace it with the wrong one. Both these where purchased from a TR7 supplier. The standard heater has rubber couplings that deteriorate with time and leak (inside cockpit) so I would be wary of putting too much pressure on the heater core. they aren't available practically speaking so people buy the replacement core that doesn't need them.

Brianc wrote:I think i will test the thermostat, then give the sustem a full flush, then fill it with the correct fluid - out of interest, being lazy, what spec is antofreeze

Brian

Blue Glycol antifreeze is generally adequate for older cars and suitable for aluminium, its what I always use. Not sure if OAT (Pink) which has a longer life is suitable but they should NOT be mixed. I generally get the blue stuff from Euro Car Parts when it is on offer, not very expensive. A 50/50 mix with water (or distilled water if you are fussy) is recommended to protect the engine.

Just by way of confirmation my engine is the rover v8 so i suspect the one on the left is correct for that engine????

The one on the right is clearly for the tr7 2 litre

Brian

Sorry, the thermostat pictures are for a TR7. The foot of the correct one (sometimes called a Triumph foot) because Triumph engines use it to block off the by pass to the engine so all the coolant is directed to the radiator for maximum cooling. The V-8 which is a Buick engine (originally) probably doesn't use it I would expect so your observation would be correct.

sheetsofsound wrote:I had the exact symptoms you describe. Turned out to be a blocked heater core and the wrong thermostat - both things previously mentioned. I didn't figure out the thermostat until I had taken the matrix out and rebuilt it. I replaced the stock heater core with one from a VW. (The VW one cost me about CAD60 instead of upwards of CAD150.) Once that was in the car, it became apparent that the thermostat was too low. Now I get lots of heat.

Could you explain a it more about the heater matrix swap and how you did it. Do you know which model your replacement core came from etc etc. Any pictures?
I am sure a lot of folks on here would love to know when they need to replace theirs.

dursleyman wrote:

sheetsofsound wrote:I had the exact symptoms you describe. Turned out to be a blocked heater core and the wrong thermostat - both things previously mentioned. I didn't figure out the thermostat until I had taken the matrix out and rebuilt it. I replaced the stock heater core with one from a VW. (The VW one cost me about CAD60 instead of upwards of CAD150.) Once that was in the car, it became apparent that the thermostat was too low. Now I get lots of heat.

Could you explain a it more about the heater matrix swap and how you did it. Do you know which model your replacement core came from etc etc. Any pictures?
I am sure a lot of folks on here would love to know when they need to replace theirs.

Me for one!
Al