Hello

I am asking you for help with the problem that yesterday spread me and two friends with whom I did it on the shoulders. I started replacing the DCCV valve because after diagnosing problems with heating at a standstill and at low revolutions it fell on it. Initially, I suspected an additional circulation pump, but as it turned out it was simply disconnected because the plug was damaged. Here, the important thing for this story is that I did it a week ago (I drained the liquid because otherwise I will not get it) and after connecting I flooded with liquid, everything was bled. The connection of the pump did not give anything so I unplugged the DCCV valve (I did not do it earlier because it was running there and the tubes for the heater were hot but the heating only worked at high speed). After disconnecting the valve (through the fuse), it started to heat up as angry at lower revs (this is the reason that the fuse also disconnects the auxiliary pump). I bought a new valve, the same procedure as before, I replaced the new plug, I flooded the liquid.
Now the magic will start - I start the engine, it walks for a few minutes and suddenly the temperature indicator flew up and boils the liquid - the thermostat did not open up in a magical way. Liquid down, thermostat to the glass, cooking and opens at the set temperature. Thermostat landed again in the car and repeat the same - there was a few hours of air fight later - after many attempts to find a place where the air cushion finally began to improve and fluid began to circulate partially and appear on returns from the radiator but to the heater fluid does not flow (valve and pump in the meantime connected and disconnected) - he must go there and yet he does not want to.
We took out the thermostat once more and started without - the engine was warming up, it kept the temperature nice, I did a quiet test drive, but the heating was totally missing. Then we disconnected the return line from the heater near the firewall, we blinded it and blew through the reservoir - a lot of air flew out, and then a stream of fluid so the heater is free because after being blinded, I was blowing fluid through the electrovalve and supply hoses so it is not blocked either. Even if I connected something badly there which is virtually impossible due to the shape and length of individual hoses, the engine was not allowed to boil (with the valve and pump connected and without) because it is a separate system from the heating. Unless it was so incredibly caught air that it completely blocked the return and there was no flow.
In conclusion - the engine without a thermostat heats up and keeps the temp properly, the heating is now completely missing and at 1:30 am we have already lost strength. We only came to the conclusion that once we have pushed the air through the heater, a water pump without a thermostat which stifles the flow of water by increasing the pressure is not able to push this water into smaller hoses only pushes those thick because it has the least resistance so tomorrow I put the thermostat back and see if it will not boil it again, or maybe it will finally put water into heating. Yet to be sure that the circulating pump works in the car (because it is checked out and working on the outside), I will remove the relay and release its voltage because otherwise I am unable to check it.

The whole situation is completely senseless because with the removed voltage from the pump and DCCV, the fluid must go to the heater, and the engine has no right to boil because nothing blocks the flow of water.

I am asking for ideas and suggestions, because I do not know what has happened here.

 

is the auxiliary coolant pump working ?
its job is to pump coolant to the heater at low rpm's.

definitely put the thermostat back in . or it will run on choke for way too long and cause other issues .

 

I checked the pump out of the car and it works - tomorrow I will remove the relay and make a bridge to check if it works in the car. The thermostat was removed only for testing and for a short ride and I know it should be mounted. I checked it out of the car and it works. As for the pump, no matter if it's connected or not, it's like a DCCV valve, because the fluid just goes through it a bit slower and you have to gently increase the speed- in any case, the fluid gets into the heater. It still worked until yesterday when I was driving a few days with the F32 fuse removed (aux pump, DCCV and AC clutch) and heating worked at a slightly higher engine speed. After replacing DCCV and yesterday's strange behavior of the cooling system, the heating is completely missing. As I wrote earlier, I will install the thermostat again because maybe after "blowing" the heater it will finally move.

 

This reads like a job for Karl

 

Can't wait to return the "favor"...

I'm a bit hesitant to wade in here. Sounds like a lot going on at once, with multiple repair attempts all happening at the same time. I'd highly suggest slowing down and concentrating on one thing at a time, versus nonstop lobbing parts in hopes of a fix. If this is your only car, you may want to make other arrangements for a few days so you're not working in a panic situation.

Some more background info would help, too. How long have you owned the car? Is this a new problem or an ongoing saga? Any other recent work?

Sounds like you've already realized this, but don't run without a thermostat. This isn't like most cars, where the thermostat is an on/off device. Instead, the S-Type thermostat is an either/or device. When hot, coolant is routed through the radiator for more cooling. When cool, coolant is sent to a radiator bypass tube for less cooling. If you take out the thermostat, most of the coolant takes the easy route and bypasses the radiator. This can easily cause overheating.

I'd also suggest testing the thermostat in a pot of water on the stove. Measure the water temperature when the thermostat opens. I've even had new ones bad from stock, so if replacing the thermostat, be sure to test it before installation.

A pressure test is probably next. Get one of those hand-pump testers that connect in place of the cap. With the engine cold, pump up the system to the rating on the cap. Make sure the system can hold pressure without dropping for at least 15 minutes, longer if possible. If the pressure drops, there is a leak that must be addressed.

These cars are VERY sensitive to cooling system pressure. If there's a leak and pressure can't build up to normal levels, the coolant flow can be erratic. No amount of bleeding will overcome that.

 

Thread to close

The cat won the battle but I won the war. Cumulation of different activities / repairs plus bad luck when venting, nervousness and fatigue. DCCV valve replaced, circulation pump replaced as it turned out unnecessarily but whatever, new liquid. Yesterday at 1:30 in the morning as we gave up the neighbor said - "you'll see that in the end it turns out that it is some simple thing failed "

In conclusion - the engine had previously been terribly infested and therefore boiled. Today I calmly flooded the system and at the end I pushed the fluid through the heater for good. We start the engine, the temperature gauge nicely and slowly raises, does not boil like before but the heating is still missing - the pipes are cold. A colleague asks - did you check the pump relay? Quick change with fog lamp relay and suddenly hot tubes and heating works

I have no questions - what we have learned during these two days is ours .

 

Awesome, good work!

 

Great job ..now you can enjoy the car and have the pride of repairing it yourself...it feels good doesn't it

 

Yes, this is a cool feeling but hush, do not talk about it loudly because the cat listens

 

You are so right on this..I cussed mine out one day and the next day the radiator blew... needless to say I learned

 

I have repeatedly convinced myself that the kitty can not tolerate criticism so I know what you are talking about